1 5222 89 PRIMARY BILIARY CIRRHOSIS: FAMILY STORIES. PRIMARY BILIARY CIRRHOSIS (PBC) IS A CHRONIC IMMUNE-MEDIATED CHOLESTATIC LIVER DISEASE OF UNKNOWN AETIOLOGY WHICH AFFECTS MOSTLY WOMEN IN MIDDLE AGE. FAMILIAL PBC IS WHEN PBC AFFECTS MORE THAN ONE MEMBER OF THE SAME FAMILY, AND DATA SUGGEST THAT FIRST-DEGREE RELATIVES OF PBC PATIENTS HAVE AN INCREASED RISK OF DEVELOPING THE DISEASE. MOST OFTEN, THESE FAMILIAL CLUSTERS INVOLVE MOTHER-DAUGHTER PAIRS, WHICH IS CONSISTENT WITH THE FEMALE PREPONDERANCE OF THE DISEASE. THESE CLUSTERS PROVIDE EVIDENCE TOWARDS A GENETIC BASIS UNDERLYING PBC. HOWEVER, CLUSTERS OF NONRELATED INDIVIDUALS HAVE ALSO BEEN REPORTED, GIVING STRENGTH TO AN ENVIRONMENTAL COMPONENT. TWIN STUDIES HAVE DEMONSTRATED A HIGH CONCORDANCE FOR PBC IN MONOZYGOTIC TWINS AND A LOW CONCORDANCE AMONG DIZYGOTIC TWINS. IN CONCLUSION, STUDIES OF PBC IN FAMILIES CLEARLY DEMONSTRATE THAT GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS PLAY A ROLE IN THE DEVELOPMENT OF THE DISEASE. 2011 2 4562 23 MYELODYSPLASTIC SYNDROME/MYELOPROLIFERATIVE NEOPLASM OVERLAP SYNDROMES: A FOCUSED REVIEW. MYELODYSPLASTIC SYNDROME (MDS)/MYELOPROLIFERATIVE NEOPLASM (MPN) OVERLAP SYNDROMES ARE UNIQUE MYELOID NEOPLASMS, WITH OVERLAPPING FEATURES OF MDS AND MPN. THEY CONSIST OF FOUR ADULT ONSET ENTITIES INCLUDING CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), MDS/MPN-RING SIDEROBLASTS-THROMBOCYTOSIS (MDS/MPN-RS-T), BCR-ABL1 NEGATIVE ATYPICAL CHRONIC MYELOID LEUKEMIA (ACML) AND MDS/MPN-UNCLASSIFIABLE (MDS/MPN-U); WITH JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) BEING THE ONLY PEDIATRIC ONSET ENTITY. AMONG THESE OVERLAP NEOPLASMS, CMML IS THE MOST FREQUENT AND IS HALLMARKED BY THE PRESENCE OF SUSTAINED PERIPHERAL BLOOD MONOCYTOSIS WITH RECURRENT MUTATIONS INVOLVING TET2 (60%), SRSF2 (50%) AND ASXL1 (40%); WITH RAS PATHWAY MUTATIONS AND JAK2V617F BEING RELATIVELY ENRICHED IN PROLIFERATIVE CMML SUBTYPES (WBC >/=13 X 109/L). CMML USUALLY PRESENTS IN THE 7TH DECADE OF LIFE, WITH A MALE PREPONDERANCE AND IS ASSOCIATED WITH A MEDIAN OVERALL SURVIVAL OF <36 MONTHS. ADVERSE PROGNOSTICATORS IN CMML INCLUDE INCREASING AGE, HIGH WBC, PRESENCE OF CIRCULATING IMMATURE MYELOID CELLS, ANEMIA, THROMBOCYTOPENIA AND TRUNCATING ASXL1 MUTATIONS. WHILE ALLOGENEIC STEM CELL TRANSPLANTATION REMAINS THE ONLY CURATIVE OPTION, GIVEN THE LATE ONSET OF THIS NEOPLASM AND HIGH FREQUENCY OF COMORBIDITIES, MOST PATIENTS REMAIN INELIGIBLE. HYPOMETHYLATING AGENTS SUCH AS AZACITIDINE, DECITABINE AND ORAL DECITABINE/CEDAZURIDINE HAVE BEEN US FDA APPROVED FOR THE MANAGEMENT OF CMML, WITH OVERALL RESPONSE RATES OF 40-50% AND COMPLETE REMISSION RATES OF <20%. WHILE THESE AGENTS EPIGENETICALLY RESTORE HEMATOPOIESIS IN A SUBSET OF RESPONDING PATIENTS, THEY DO NOT IMPACT MUTATIONAL ALLELE BURDENS AND EVENTUAL DISEASE PROGRESSION TO AML REMAINS INEVITABLE. NEWER TREATMENT MODALITIES EXPLOITING EPIGENETIC, SIGNALING AND SPLICING ABNORMALITIES COMMONLY SEEN IN CMML ARE MUCH NEEDED. 2020 3 3383 22 HNF1B NEPHROPATHY HAS A SLOW-PROGRESSIVE PHENOTYPE IN CHILDHOOD-WITH THE EXCEPTION OF VERY EARLY ONSET CASES: RESULTS OF THE GERMAN MULTICENTER HNF1B CHILDHOOD REGISTRY. BACKGROUND: HNF1B GENE MUTATIONS ARE AN IMPORTANT CAUSE OF BILATERAL (CYSTIC) DYSPLASIA IN CHILDREN, COMPLICATED BY CHRONIC RENAL INSUFFICIENCY. THE CLINICAL VARIABILITY, THE ABSENCE OF GENOTYPE-PHENOTYPE CORRELATIONS, AND LIMITED LONG-TERM DATA RENDER COUNSELING OF AFFECTED FAMILIES DIFFICULT. METHODS: LONGITUDINAL DATA OF 62 CHILDREN PROBANDS WITH GENETICALLY PROVEN HNF1B NEPHROPATHY WAS OBTAINED IN A MULTICENTER APPROACH. GENETIC FAMILY CASCADE SCREENING WAS PERFORMED IN 30/62 CASES. RESULTS: EIGHTY-SEVEN PERCENT OF PATIENTS HAD BILATERAL DYSPLASIA, 74% VISIBLE BILATERAL, AND 16% UNILATERAL RENAL CYSTS AT THE END OF OBSERVATION. CYST DEVELOPMENT WAS NON-PROGRESSIVE IN 72% WITH A MEAN GLOMERULAR FILTRATION RATE (GFR) LOSS OF - 0.33 ML/MIN/1.73M(2) PER YEAR (+/- 8.9). IN PATIENTS WITH AN INCREASE IN CYST NUMBER, THE ANNUAL GFR REDUCTION WAS - 2.8 ML/MIN/1.73M(2) (+/- 13.2), IN THE TOTAL COHORT - 1.0 ML/MIN/1.73M(2) (+/-10.3). A SUBSET OF HNF1B PATIENTS DIFFERS FROM THIS GROUP AND DEVELOPS END STAGE RENAL DISEASE (ESRD) AT VERY EARLY AGES < 2 YEARS. HYPERURICEMIA (37%) WAS A FREQUENT FINDING AT YOUNG AGE (MEDIAN 1 YEAR), WHEREAS HYPOMAGNESEMIA (24%), ELEVATED LIVER ENZYMES (21%), AND HYPERGLYCEMIA (8%) SHOWED AN INCREASED INCIDENCE IN THE TEENAGED CHILD. GENETIC ANALYSIS REVEALED NO GENOTYPE-PHENOTYPE CORRELATIONS BUT A SIGNIFICANT PARENT-OF-ORIGIN EFFECT WITH A PREPONDERANCE OF 81% OF MATERNAL INHERITANCE IN DOMINANT CASES. CONCLUSIONS: IN MOST CHILDREN, HNF1B NEPHROPATHY HAS A NON-PROGRESSIVE COURSE OF CYST DEVELOPMENT AND A SLOW-PROGRESSIVE COURSE OF KIDNEY FUNCTION. A SUBGROUP OF PATIENTS DEVELOPED ESRD AT VERY YOUNG AGE < 2 YEARS REQUIRING SPECIAL MEDICAL ATTENTION. THE PARENT-OF-ORIGIN EFFECT SUGGESTS AN INFLUENCE OF EPIGENETIC MODIFIERS IN HNF1B DISEASE. 2019 4 3112 39 GEOEPIDEMIOLOGY AND (EPI-)GENETICS IN PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A RARE FEMALE PREPONDERANT CHRONIC AUTOIMMUNE CHOLESTATIC LIVER DISEASE, CHARACTERIZED BY INTRAHEPATIC DUCTOPENIA AND PROGRESSIVE FIBROSIS. DURING LAST DECADES INCIDENCE AND PREVALENCE SHOWED AN INCREASING RATE WHICH VARY WIDELY WORLDWIDE DEMONSTRATING AN IMPORTANT INTERACTION BETWEEN ENVIRONMENTAL AND GENETIC FACTORS. HERITABILITY SUGGESTED BY FAMILIAL OCCURRENCE AND MONOZYGOTIC TWINS CONCORDANCE HAVE BEEN CONFIRMED IN MORE STUDIES. EPIGENETICS MECHANISMS SUCH AS HISTONE MODIFICATION AND DNA METHYLATION CAN PARTIALLY EXPLAIN PREDISPOSITION AND INHERITANCE OF THIS DISEASE. NEVERTHELESS, AN ASSOCIATION WITH SPECIFIC CLASS II HUMAN LEUKOCYTE ANTIGEN (HLA) VARIANTS HAVE BEEN REPORTED, SHOWING AN INCREASE RISK IN SUSCEPTIBILITY. MORE RECENTLY, DATA REGARDING A STRONG PROTECTIVE ASSOCIATION BETWEEN PBC AND HLA ALLELES CONFIRMED THIS ASSOCIATION. AFTER RECENT GENOME-WIDE ASSOCIATION STUDIES (GWAS), A MORE INTRICATE INTERACTION BETWEEN PBC AND THE HLA REGION HAS BEEN SHOWN. FURTHERMORE, GWAS ALSO IDENTIFIED SEVERAL IMMUNE-RELATED-GENES IMPLICATED. MORE GENOME-WIDE ASSOCIATION STUDIES ON THIS DISEASE ARE NEEDED TO REACH A COMPLETE AND SYSTEMATIC KNOWLEDGE OF THIS DISEASE. IN THIS REVIEW WE DISCUSS MORE RECENT ISSUED DATA ON GEOEPIDEMIOLOGY OF PBC AND THE ROLE OF (EPI-)GENETIC MECHANISMS IN ITS PATHOGENESIS. 2018 5 3012 30 GENETICS AND EPIGENETICS IN THE PATHOGENESIS OF PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC, SLOWLY PROGRESSIVE CHOLESTATIC AUTOIMMUNE LIVER DISEASE PREDOMINANTLY AFFLICTING WOMEN. PBC IS CHARACTERIZED BY THE PRESENCE OF DISEASE-SPECIFIC ANTIMITOCHONDRIAL ANTIBODIES AND THE HISTOLOGICAL DESTRUCTION OF INTRAHEPATIC BILE DUCTS, WHICH EVENTUALLY LEAD TO CIRRHOSIS AND HEPATIC FAILURE. FORTUNATELY, URSODEOXYCHOLIC ACID THERAPY HAS IMPROVED THE OUTCOME OF THE VAST MAJORITY OF PBC CASES. ALTHOUGH THE ETIOLOGY OF PBC HAS NOT YET BEEN ELUCIDATED, HUMAN LEUKOCYTE ANTIGEN (HLA) CLASS II ALLELES HAVE BEEN CONSISTENTLY ASSOCIATED WITH DISEASE ONSET FOR DECADES. PBC PATIENTS MAY ALSO HAVE GENETICALLY DETERMINED RISK FACTORS IN NON-HLA REGIONS. MEANWHILE, EXPOSURE TO ENVIRONMENTAL FACTORS, SUCH AS INFECTIOUS DISEASES AND HARMFUL CHEMICALS, CAN PRODUCE EPIGENETIC ALTERATIONS IN SOME INDIVIDUALS AND SUBSEQUENT PBC ONSET. IN THIS REVIEW, WE DESCRIBE THE INFLUENCE OF HLA ALLELES AND OTHER GENE POLYMORPHISMS ON PBC ALONG WITH THE RESULTS OF GENOME-WIDE ASSOCIATION STUDIES ON THIS DISEASE AND ITS FUTURE PROSPECTS IN TERMS OF EPIGENETICS. 2018 6 2512 38 EPIGENETICS AND PRIMARY BILIARY CIRRHOSIS: A COMPREHENSIVE REVIEW AND IMPLICATIONS FOR AUTOIMMUNITY. PRIMARY BILIARY CIRRHOSIS (PBC) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE THAT DEVELOPS BASED UPON THE INTERACTION OF GENETIC AND ENVIRONMENTAL FACTORS. RECENT GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED DOZENS OF PREDISPOSING VARIANTS INCLUDING HLA, IL12A, AND CTLA4 BUT HAVE BEEN DISAPPOINTED IN IDENTIFYING A "SMOKING GUN." THESE DISCOVERIES HIGHLIGHT THE IMPORTANCE OF THE GENETIC BACKGROUND INVOLVED IN IMMUNOLOGICAL DYSREGULATION. ALTHOUGH CONCORDANCE RATE OF PBC IN MONOZYGOTIC (MZ) TWINS IS AMONG THE HIGHEST REPORTED IN AUTOIMMUNE DISORDERS, INCOMPLETE DISEASE CONCORDANCE IN TWINS ASSOCIATED WITH DIFFERENTIALLY EXPRESSED GENES HAS BEEN DEMONSTRATED. HOWEVER, LITTLE IS UNDERSTOOD ABOUT HOW ENVIRONMENTAL ASPECTS CONTRIBUTE TO THE DISEASE AND WHY MIDDLE-AGED WOMEN ARE MORE SUSCEPTIBLE. AS A RESULT, EPIGENETIC FACTORS, WHICH CONVERT SIGNALS INDICATING ENVIRONMENTAL CHANGES INTO DYNAMIC AND HERITABLE ALTERATIONS OF TRANSCRIPTIONAL POTENTIAL, ARE GETTING INCREASED ATTENTION BY RESEARCHERS IN BOTH BASIC AND CLINICAL STUDIES. AMONG EPIGENETIC MECHANISMS, THE INSTABILITY AND SKEWED GENE EXPRESSION IN THE X CHROMOSOME MAY ACCOUNT FOR THE FEMALE PREPONDERANCE IN PBC. IN ADDITION, TRANSCRIPTIONAL REGULATION OF HISTONE MODIFICATION AND DNA METHYLATION UNDERSCORES POTENTIAL INVOLVEMENT IN DISEASE PATHOGENESIS. HIGH-THROUGHPUT TECHNIQUES ARE BEING USED TO IDENTIFY EPIGENETIC REGULATORS. IN THIS REVIEW, WE ATTEMPT TO OUTLINE RECENT PROGRESS REGARDING EPIGENETICS IN PBC AND OTHER AUTOIMMUNE DISEASES. 2016 7 5506 34 RHEUMATOID ARTHRITIS AND PRIMARY BILIARY CIRRHOSIS: CAUSE, CONSEQUENCE, OR COINCIDENCE? PRIMARY BILIARY CIRRHOSIS (PBC) IS A PROGRESSIVE CHOLESTATIC LIVER DISEASE CHARACTERIZED SEROLOGICALLY BY CHOLESTASIS AND THE PRESENCE OF HIGH-TITRE ANTIMITOCHONDRIAL ANTIBODIES AND HISTOLOGICALLY BY CHRONIC NONSUPPURATIVE CHOLANGITIS AND GRANULOMATA. PBC PATIENTS OFTEN HAVE CONCOMITANT AUTOIMMUNE DISEASES, INCLUDING ARTHROPATHIES. THIS RAISES THE QUESTION AS TO WHETHER THERE ARE SHARED FEATURES IN THE PATHOGENESIS OF THOSE DISEASES WITH THE PATHOGENESIS OF PBC. EPIDEMIOLOGICAL AND LARGE CASE STUDIES HAVE INDICATED THAT ALTHOUGH THE INCIDENCE OF RHEUMATOID ARTHRITIS (RA) IS NOT SIGNIFICANTLY RAISED IN PBC PATIENTS, THERE APPEARS TO BE A HIGHER RATE OF RA IN PBC PATIENTS AND THEIR RELATIVES. GENETIC STUDIES HAVE DEMONSTRATED THAT SEVERAL GENES IMPLICATED IN PBC HAVE ALSO BEEN IMPLICATED IN RA. EPIGENETIC STUDIES PROVIDED A WEALTH OF DATA REGARDING RA, BUT THE FINDINGS ON EPIGENETIC CHANGES IN PBC ARE VERY LIMITED. AS WELL, CERTAIN INFECTIOUS AGENTS IDENTIFIED IN THE PATHOGENESIS OF PBC MAY ALSO PLAY A ROLE IN THE PATHOGENESIS OF RA. THESE DATA SUGGEST THAT ALTHOUGH RA IS NOT SIGNIFICANTLY PRESENT IN PBC, SOME INDIVIDUALS WITH CERTAIN GENETIC TRAITS AND ENVIRONMENTAL EXPOSURES MAY DEVELOP BOTH CONDITIONS. THIS CONCEPT MAY ALSO APPLY TO OTHER CONCOMITANT DISEASES FOUND IN PBC PATIENTS. 2012 8 6714 23 VISION OF RESEARCH ON HUMAN LINEAR GROWTH. THE HUMAN BODY GROWS IN LENGTH FROM CONCEPTION TO THE MAXIMAL ADULT HEIGHT OVER TWO DECADES. THE SHORTEST MALE POPULATION AVERAGES APPROXIMATELY 150 CM AND THE TALLEST APPROXIMATELY 183 CM. NONETHELESS THE DIMENSIONS OF HEAD AND TRUNK ARE HIGHLY COMPARABLE, WITH THE VAST DIFFERENCE IN THE LEG LENGTH. STUNTING IS A PERSONAL CONDITION IN WHICH AN INDIVIDUAL HAS A STANDING HEIGHT-FOR-AGE (HAZ) OF LESS THAN TWO STANDARD DEVIATIONS OF THE STANDARD CURVE MEDIAN. IT IS ASSOCIATED WITH INCREASED MORTALITY, MORBIDITY, AND FUNCTIONAL DEFICITS. THE PROCESS OF LOSING RELATIVE STATURE IS KNOWN AS LINEAR GROWTH RETARDATION, FIRST ATTRIBUTED TO CHRONIC PROTEIN DEFICIENCY, THEN TO AN ASSORTMENT OF MICRONUTRIENT DEFICIENCIES, AND MOST RECENTLY TO INFLAMMATION FROM UNHYGIENIC ENVIRONMENTAL CONDITIONS. PUBLIC HEALTH INTERVENTION TRIALS RESPONDING TO EACH OF THESE POSSIBILITIES HAVE FAILED TO PRODUCE TRUE REVERSAL RESPONSES MEASURED IN THE 10S OF CENTIMETERS. AS TO BIOLOGICAL INSIGHTS, THERE IS NO CONVENIENT WAY TO SEPARATE WEIGHT FROM LENGTH GROWTH WITH SONOGRAPHIC MONITORING, BUT A THIRD OF INFANTS CAN BE BORN STUNTED. NORMATIVE GROWTH (STANDARD CURVES) COMPETES WITH EPIGENETIC ADAPTATION (PROGRAMMING) AS THE BEACON FOR IN UTERO GROWTH. MAJOR INVESTMENTS INTO FIELD TRIALS ALLOW US TO DISCARD MULTIPLE MICRONUTRIENTS AND WATER/SANITATION/HYGIENE INTERVENTIONS AS MEASURES TO REVERSE ESTABLISHED STUNTING. THE PREPONDERANCE OF EVIDENCE IS AGAINST CATCH-UP GROWTH DURING PUBERTY. FUTURE PUBLICATIONS WILL BE IN THE CONCEPTUAL DOMAIN, RESOLVING METRICS, WHILE THE FULL RANGE OF STIMULI AND EXPOSURES IMPEDING GROWTH WILL BE ELUCIDATED. ADVANCES IN MEASUREMENT TECHNIQUES IN ANTHROPOMETRY AND IMMUNOLOGY AND ENDOCRINOLOGY WILL BE MOBILIZED TO THE LITERATURE. 2019 9 5220 28 PRIMARY BILIARY CHOLANGITIS: A TALE OF EPIGENETICALLY-INDUCED SECRETORY FAILURE? PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC CHOLESTATIC LIVER DISEASE ASSOCIATED WITH AUTOIMMUNE-RELATED DESTRUCTION OF SMALL TO MEDIUM SIZE INTRAHEPATIC BILE DUCTS. THE AETIOLOGY OF PBC IS UNKNOWN AND ITS PATHOGENESIS REMAINS OBSCURE. BOTH GENETIC VARIANTS AND ENVIRONMENTAL FACTORS HAVE BEEN LINKED TO INCREASED PBC SUSCEPTIBILITY, WITH OTHER ALTERATIONS KNOWN TO COOPERATE IN DISEASE PATHOBIOLOGY. INCREASING EVIDENCE INDICATES THE PRESENCE OF EPIGENETIC ABNORMALITIES IN PBC, PARTICULARLY ALTERATIONS OF CHOLANGIOCELLULAR MICRORNAS (MIRNAS OR MIRS). THIS REVIEW HIGHLIGHTS AND DISCUSSES THE MOST RELEVANT EPIGENETIC ALTERATIONS FOUND IN PATIENTS WITH PBC, FOCUSING ON THE ROLE OF MIR-506 IN THE PROMOTION OF CHOLESTASIS AND IMMUNE ACTIVATION. 2018 10 2588 32 EPIGENETICS OF PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC CHOLESTATIC LIVER DISEASE WITH NON-SUPPURATIVE DESTRUCTION OF THE INTRAHEPATIC BILE DUCTS. THE INTERPLAY OF GENETICS AND ENVIRONMENTAL TRIGGERS CONTRIBUTES TO THE ONSET OF THE DISEASE AND SUBSEQUENTLY RESULTS IN CHOLESTASIS AND PROGRESSIVE FIBROSIS. RECENTLY, GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED MULTIPLE GENES INFLUENCING THE SUSCEPTIBILITY TO PBC IN HLA AND NON-HLA LOCI. HOWEVER, IT IS ESTIMATED THAT THE KNOWN RISK VARIANTS MERELY ACCOUNT FOR NO MORE THAN 20% OF THE HERITABILITY OF PBC AND CAUSES OF THE REMAINING HERITABILITY REMAIN UNCERTAIN. INCREASING EVIDENCE SUGGESTS THAT THE PRESENCE OF EPIGENETIC ABNORMALITIES MAY EXPLAIN THE "MISSING HERITABILITY" THAT CANNOT BE CAPTURED BY GWAS. AMONG THESE EPIGENETIC MECHANISMS, DNA METHYLATION, HISTONE MODIFICATION, AND NONCODING RNAS (I.E. MIRNA AND LNCRNA) ARE INVOLVED IN THE PATHOGENESIS OF PBC. ADDITIONALLY, TELOMERE DYSREGULATION IN BILIARY EPITHELIAL CELLS (BECS) MAY PLAY A ROLE IN DISEASE ONSET, WHEREAS A DEFICIENCY IN SEX CHROMOSOME AND SKEWED GENE EXPRESSION IN THE X CHROMOSOME MAY TO SOME EXTENT EXPLAIN THE FEMALE DOMINANCE IN PBC. 2020 11 3872 21 JUVENILE MYELOMONOCYTIC LEUKEMIA-A COMPREHENSIVE REVIEW AND RECENT ADVANCES IN MANAGEMENT. JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) IS A RARE PEDIATRIC MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASM OVERLAP DISEASE. JMML IS ASSOCIATED WITH MUTATIONS IN THE RAS PATHWAY GENES RESULTING IN THE MYELOID PROGENITORS BEING SENSITIVE TO GRANULOCYTE MONOCYTE COLONY-STIMULATING FACTOR (GM-CSF). KARYOTYPE ABNORMALITIES AND ADDITIONAL EPIGENETIC ALTERATIONS CAN ALSO BE FOUND IN JMML. NEUROFIBROMATOSIS AND NOONAN'S SYNDROME HAVE A PREDISPOSITION FOR JMML. IN A FEW PATIENTS, THE RAS GENES (NRAS, KRAS, AND PTPN11) ARE MUTATED AT THE GERMLINE AND THIS USUALLY RESULTS IN A TRANSIENT MYELOPROLIFERATIVE DISORDER WITH A GOOD PROGNOSIS. JMML WITH SOMATIC RAS MUTATION BEHAVES AGGRESSIVELY. JMML PRESENTS WITH CYTOPENIAS AND LEUKEMIC INFILTRATION INTO ORGANS. THE LABORATORY FINDINGS INCLUDE HYPERLEUKOCYTOSIS, MONOCYTOSIS, INCREASED HEMOGLOBIN-F LEVELS, AND CIRCULATING MYELOID PRECURSORS. THE BLAST CELLS IN THE PERIPHERAL BLOOD/BONE-MARROW ASPIRATE ARE LESS THAN 20% AND THE ABSENCE OF THE BCR-ABL TRANSLOCATION HELPS TO DIFFERENTIATE FROM CHRONIC MYELOID LEUKEMIA. JMML SHOULD BE DIFFERENTIATED FROM IMMUNODEFICIENCIES, VIRAL INFECTIONS, INTRAUTERINE INFECTIONS, HEMOPHAGOLYMPHOHISTIOCYTOSIS, OTHER MYELOPROLIFERATIVE DISORDERS, AND LEUKEMIAS. CHEMOTHERAPY IS EMPLOYED AS A BRIDGE TO HSCT, EXCEPT IN FEW WITH LESS AGGRESSIVE DISEASE, IN WHICH CHEMOTHERAPY ALONE CAN RESULT IN LONG TERM REMISSION. AZACITIDINE HAS SHOWN PROMISE AS A SINGLE AGENT TO STABILIZE THE DISEASE. THE PROGNOSIS OF JMML IS POOR WITH ABOUT 50% OF PATIENTS SURVIVING AFTER AN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT (HSCT). ALLOGENEIC HSCT IS THE ONLY KNOWN CURE FOR JMML TO DATE. MYELOABLATIVE CONDITIONING IS MOST COMMONLY USED WITH GRAFT VERSUS HOST DISEASE (GVHD) PROPHYLAXIS TAILORED TO THE AGGRESSIVENESS OF THE DISEASE. RELAPSES ARE COMMON EVEN AFTER HSCT AND A SECOND HSCT CAN SALVAGE A THIRD OF THESE PATIENTS. NOVEL OPTIONS IN THE TREATMENT OF JMML E.G., HYPOMETHYLATING AGENTS, MEK INHIBITORS, JAK INHIBITORS, TYROSINE KINASE INHIBITORS, ETC. ARE BEING EXPLORED. 2021 12 960 17 CHRONIC MYELOMONOCYTIC LEUKEMIA: 2016 UPDATE ON DIAGNOSIS, RISK STRATIFICATION, AND MANAGEMENT. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL HEMATOPOIETIC STEM CELL DISORDER CHARACTERIZED BY OVERLAPPING FEATURES OF MYELODYSPLASTIC SYNDROMES AND MYELOPROLIFERATIVE NEOPLASMS. DIAGNOSIS IS BASED ON THE PRESENCE OF PERSISTENT (>3 MONTHS) PERIPHERAL BLOOD MONOCYTOSIS (>1 X 10(9) /L), ALONG WITH BONE MARROW DYSPLASIA. CLONAL CYTOGENETIC ABNORMALITIES OCCUR IN APPROXIMATELY 20-30% OF PATIENTS, WHILE >90% HAVE GENE MUTATIONS. MUTATIONS INVOLVING TET2 ( APPROXIMATELY 60%), SRSF2 ( APPROXIMATELY 50%), ASXL1 ( APPROXIMATELY 40%), AND RAS ( APPROXIMATELY 30%) ARE FREQUENT; WITH ONLY ASXL1 MUTATIONS NEGATIVELY IMPACTING OVERALL SURVIVAL. TWO MOLECULARLY INTEGRATED, CMML-SPECIFIC PROGNOSTIC MODELS INCLUDE; THE GROUPE FRANCAIS DES MYELODYSPLASIES (GFM) AND THE MOLECULAR MAYO MODEL (MMM). THE GFM MODEL SEGREGATES PATIENTS INTO 3 GROUPS BASED ON: AGE >65 YEARS, WBC >15 X 10(9) /L, ANEMIA, PLATELETS <100 X 10(9) /L, AND ASXL1 MUTATION STATUS, WITH RESPECTIVE MEDIAN SURVIVALS OF 56 (LOW), 27.4 (INTERMEDIATE), AND 9.2 (HIGH) MONTHS. THE MMM IS BASED ON ASXL1 MUTATIONAL STATUS, ABSOLUTE MONOCYTE COUNT >10 X 10(9) /L, HEMOGLOBIN <10 G/DL, PLATELETS <100 X 109/L AND CIRCULATING IMMATURE MYELOID CELLS. THIS MODEL STRATIFIES PATIENTS INTO FOUR GROUPS; HIGH (>/=3 RISK FACTORS), INTERMEDIATE-2 (2 RISK FACTORS), INTERMEDIATE-1 (1 RISK FACTOR) AND LOW (NO RISK FACTORS), WITH MEDIAN SURVIVALS OF 16, 31, 59, AND 97 MONTHS, RESPECTIVELY. HYPOMETHYLATING AGENTS SUCH AS 5-AZACITIDINE AND DECITABINE ARE COMMONLY USED, WITH OVERALL RESPONSE RATES OF APPROXIMATELY 30-40% AND COMPLETE REMISSION RATES OF APPROXIMATELY 7-17%. ALLOGENEIC STEM CELL TRANSPLANT IS THE ONLY POTENTIALLY CURATIVE OPTION, BUT IS ASSOCIATED WITH SIGNIFICANT MORBIDITY AND MORTALITY. INDIVIDUALIZED THERAPY, INCLUDING EPIGENETIC MODIFIERS AND SMALL MOLECULE INHIBITORS, ARE EXCITING PROSPECTS. AM. J. HEMATOL. 91:632-642, 2016. (C) 2016 WILEY PERIODICALS, INC. 2016 13 961 17 CHRONIC MYELOMONOCYTIC LEUKEMIA: A GENETIC AND CLINICAL UPDATE. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL STEM CELL DISORDER, CHARACTERIZED BY PERIPHERAL BLOOD MONOCYTOSIS AND OVERLAPPING FEATURES BETWEEN MYELODYSPLASTIC SYNDROMES (MDS) AND MYELOPROLIFERATIVE NEOPLASMS (MPNS). CLONAL CYTOGENETIC CHANGES ARE SEEN IN UP TO 30 % PATIENTS, WHILE APPROXIMATELY 90 % HAVE DETECTABLE MOLECULAR ABNORMALITIES. MOST PATIENTS ARE DIAGNOSED IN THE SEVENTH DECADE OF LIFE. GENE MUTATIONS IN TEN-ELEVEN TRANSLOCATION (TET) ONCOGENE FAMILY MEMBER 2 (TET2) (60 %), SRSF2 (50 %), ASXL1 (40 %), AND RAS (20-30 %) ARE FREQUENT, WITH ONLY FRAME SHIFT AND NONSENSE ASXL1 MUTATIONS NEGATIVELY IMPACTING OVERALL SURVIVAL. WITH THE LACK OF FORMAL GUIDELINES, MANAGEMENT AND RESPONSE CRITERIA ARE OFTEN EXTRAPOLATED FROM MDS AND MPN. CONTEMPORARY MOLECULARLY INTEGRATED CMML-SPECIFIC PROGNOSTIC MODELS INCLUDE THE GROUPE FRANCAIS DES MYELODYSPLASIES (GFM) MODEL AND THE MOLECULAR MAYO MODEL, BOTH INCORPORATING ASXL1 MUTATIONAL STATUS. HYPOMETHYLATING AGENTS AND ALLOGENEIC STEM CELL TRANSPLANT REMAIN THE TWO MOST COMMONLY USED TREATMENT STRATEGIES, WITH SUBOPTIMAL RESULTS. CLINICAL TRIALS EXPLOITING EPIGENETIC AND SIGNAL PATHWAY ABNORMALITIES, FREQUENT IN CMML, OFFER HOPE AND PROMISE. 2015 14 962 22 CHRONIC MYELOMONOCYTIC LEUKEMIA: FOCUS ON CLINICAL PRACTICE. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL STEM CELL DISORDER WITH FEATURES THAT OVERLAP THOSE OF MYELODYSPLASTIC SYNDROMES (MDSS) AND MYELOPROLIFERATIVE NEOPLASMS (MPNS). CHRONIC MYELOMONOCYTIC LEUKEMIA OFTEN RESULTS IN PERIPHERAL BLOOD MONOCYTOSIS AND HAS AN INHERENT TENDENCY TO TRANSFORM TO ACUTE MYELOID LEUKEMIA. CLONAL CYTOGENETIC CHANGES ARE SEEN IN APPROXIMATELY 30% OF PATIENTS, AND MOLECULAR ABNORMALITIES ARE SEEN IN MORE THAN 90%. GENE MUTATIONS INVOLVING TET2 ( APPROXIMATELY 60%), SRSF2 ( APPROXIMATELY 50%), ASXL1 ( APPROXIMATELY 40%), AND RAS ( APPROXIMATELY 30%) ARE FREQUENT, WITH NONSENSE AND FRAMESHIFT ASXL1 MUTATIONS BEING THE ONLY MUTATIONS IDENTIFIED THUS FAR TO HAVE AN INDEPENDENT NEGATIVE PROGNOSTIC EFFECT ON OVERALL SURVIVAL. CONTEMPORARY MOLECULARLY INTEGRATED PROGNOSTIC MODELS (INCLUSIVE OF ASXL1 MUTATIONS) INCLUDE THE MOLECULAR MAYO MODEL AND THE GROUPE FRANCAIS DES MYELODYSPLASIES MODEL. GIVEN THE LACK OF FORMAL TREATMENT AND RESPONSE CRITERIA, MANAGEMENT OF CMML IS OFTEN EXTRAPOLATED FROM MDS AND MPN, WITH ALLOGENEIC STEM CELL TRANSPLANT BEING THE ONLY CURATIVE OPTION. HYDROXYUREA AND OTHER CYTOREDUCTIVE AGENTS HAVE BEEN USED TO CONTROL MPN-LIKE FEATURES, WHILE EPIGENETIC MODIFIERS SUCH AS HYPOMETHYLATING AGENTS HAVE BEEN USED FOR MDS-LIKE FEATURES. GIVEN THE RELATIVELY POOR RESPONSE TO THESE AGENTS AND THE INHERENT RISKS ASSOCIATED WITH HEMATOPOIETIC STEM CELL TRANSPLANT, NEWER DRUGS EXPLOITING MOLECULAR AND EPIGENETIC ABNORMALITIES IN CMML ARE BEING DEVELOPED. THE CREATION OF CMML-SPECIFIC RESPONSE CRITERIA IS A MUCH NEEDED STEP IN ORDER TO IMPROVE CLINICAL OUTCOMES. 2016 15 2142 38 EPIGENETIC INVESTIGATION OF VARIABLY X CHROMOSOME INACTIVATED GENES IN MONOZYGOTIC FEMALE TWINS DISCORDANT FOR PRIMARY BILIARY CIRRHOSIS. PRIMARY BILIARY CIRRHOSIS (PBC) IS AN AUTOIMMUNE CHRONIC CHOLESTATIC LIVER DISEASE WITH A STRONG GENETIC SUSCEPTIBILITY DUE TO THE HIGH CONCORDANCE IN MONOZYGOTIC (MZ) TWINS AND A STRIKING FEMALE PREDOMINANCE. WOMEN WITH PBC MANIFEST AN ENHANCED X MONOSOMY RATE IN PERIPHERAL LYMPHOCYTES AND WE THUS HYPOTHESIZED AN X CHROMOSOME EPIGENETIC COMPONENT TO EXPLAIN PBC FEMALE PREVALENCE. WHILE MOST GENES ON THE FEMALE INACTIVE X CHROMOSOME ARE SILENCED BY PROMOTER METHYLATION FOLLOWING X CHROMOSOME INACTIVATION (XCI), APPROXIMATELY 10% OF X- LINKED GENES EXHIBIT VARIABLE ESCAPE FROM XCI IN HEALTHY FEMALES. THIS STUDY WAS DESIGNED TO TEST THE HYPOTHESIS THAT SUSCEPTIBILITY TO PBC IS MODIFIED BY ONE OR MORE X-LINKED GENE WITH VARIABLE XCI STATUS. PERIPHERAL BLOOD MRNA AND DNA SAMPLES WERE OBTAINED FROM A UNIQUE COHORT OF MZ TWIN SETS DISCORDANT AND CONCORDANT FOR PBC. TRANSCRIPT LEVELS OF THE 125 VARIABLE XCI STATUS GENES WAS DETERMINED BY QUANTITATIVE RT-PCR ANALYSIS AND TWO GENES (CLIC2 AND PIN4) WERE IDENTIFIED AS CONSISTENTLY DOWNREGULATED IN THE AFFECTED TWIN OF DISCORDANT PAIRS. BOTH CLIC2 AND PIN4 DEMONSTRATED PARTIAL AND VARIABLE METHYLATION OF CPG SITES WITHIN 300 BP OF THE TRANSCRIPTION START SITE THAT DID NOT PREDICT THE XCI STATUS. PROMOTER METHYLATION OF CLIC2 MANIFESTED NO SIGNIFICANT DIFFERENCE BETWEEN SAMPLES AND NO SIGNIFICANT CORRELATION WITH TRANSCRIPT LEVELS. PIN4 METHYLATION SHOWED A POSITIVE TREND WITH TRANSCRIPTION IN ALL SAMPLES BUT NO DIFFERENTIAL METHYLATION WAS OBSERVED BETWEEN DISCORDANT TWINS. A GENETIC POLYMORPHISM AFFECTING THE NUMBER OF CPG SITES IN THE PIN4 PROMOTER DID NOT IMPACT METHYLATION OR TRANSCRIPT LEVELS IN A HETEROZYGOUS TWIN PAIR AND SHOWED A SIMILAR FREQUENCY IN INDEPENDENT SERIES OF UNRELATED PBC CASES AND CONTROLS. OUR RESULTS SUGGEST THAT EPIGENETIC FACTORS INFLUENCING PBC ONSET ARE MORE COMPLEX THAN METHYLATION DIFFERENCES AT X-LINKED PROMOTERS AND VARIABLY 3 INACTIVATED X-LINKED GENES MAY BE CHARACTERIZED BY PARTIAL PROMOTER METHYLATION AND BIALLELIC TRANSCRIPTION. 2011 16 4471 20 MOLECULAR PATHOGENESIS OF ATYPICAL CML, CMML AND MDS/MPN-UNCLASSIFIABLE. ACCORDING TO THE 2008 WHO CLASSIFICATION, THE CATEGORY OF MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASMS (MDS/MPN) INCLUDES ATYPICAL CHRONIC MYELOID LEUKAEMIA (ACML), CHRONIC MYELOMONOCYTIC LEUKAEMIA (CMML), MDS/MPN-UNCLASSIFIABLE (MDS/MPN-U), JUVENILE MYELOMONOCYTIC LEUKAEMIA (JMML) AND A "PROVISIONAL" ENTITY, REFRACTORY ANAEMIA WITH RING SIDEROBLASTS AND THROMBOCYTOSIS (RARS-T). THE REMARKABLE PROGRESS IN OUR UNDERSTANDING OF THE SOMATIC PATHOGENESIS OF MDS/MPN HAS MADE IT CLEAR THAT THERE IS CONSIDERABLE OVERLAP AMONG THESE DISEASES AT THE MOLECULAR LEVEL, AS WELL AS LAYERS OF UNEXPECTED COMPLEXITY. DEREGULATION OF SIGNALLING PLAYS AN IMPORTANT ROLE IN MANY CASES, AND IS CLEARLY LINKED TO MORE HIGHLY PROLIFERATIVE DISEASE. OTHER MUTATIONS AFFECT A RANGE OF OTHER ESSENTIAL, INTERRELATED CELLULAR MECHANISMS, INCLUDING EPIGENETIC REGULATION, RNA SPLICING, TRANSCRIPTION, AND DNA DAMAGE RESPONSE. THE VARIOUS COMBINATIONS OF MUTATIONS INDICATE A MULTI-STEP PATHOGENESIS, WHICH LIKELY CONTRIBUTES TO THE MARKED CLINICAL HETEROGENEITY OF THESE DISORDERS. THE DELINEATION OF COMPLEX CLONAL ARCHITECTURES MAY SERVE AS THE CORNERSTONE FOR THE IDENTIFICATION OF NOVEL THERAPEUTIC TARGETS AND LEAD TO BETTER PATIENT OUTCOMES. THIS REVIEW SUMMARIZES SOME OF THE CURRENT KNOWLEDGE OF MOLECULAR PATHOGENETIC LESIONS IN THE MDS/MPN SUBTYPES THAT ARE SEEN IN ADULTS: ATYPICAL CML, CMML AND MDS/MPN-U. 2015 17 2192 27 EPIGENETIC METHODS AND TWIN STUDIES. GENOMIC PREDISPOSITION FAILS TO FULLY EXPLAIN THE ONSET OF COMPLEX DISEASES, WHICH IS WELL ILLUSTRATED BY THE LARGELY INCOMPLETE CONCORDANCE AMONG MONOZYGOTIC TWINS. EPIGENETIC MECHANISMS, INCLUDING DNA METHYLATION, CHROMATIN REMODELING, AND NON-CODING RNA, ARE THE LINK BETWEEN ENVIRONMENTAL STIMULI AND DISEASE ONSET ON A PERMISSIVE GENETIC BACKGROUND IN AUTOIMMUNE AND CHRONIC INFLAMMATORY DISEASES. AUTOIMMUNE DISEASES NOW INCLUDE ALMOST 100 CONDITIONS AND ARE ESTIMATED TO CUMULATIVELY AFFECT UP TO 5% OF THE WORLD POPULATION WITH A HEALTHCARE EXPENDITURE SUPERIOR TO CANCER WORLDWIDE. MANY ADVANCES IN MEDICINE HAVE BEEN MADE TO TREAT THESE CONDITIONS BUT THERE ARE STILL GAPS, AND AN INNOVATIVE AND EFFICIENT THERAPY IS NEEDED. SYSTEMIC AUTOIMMUNE DISEASES INCLUDE RHEUMATOID ARTHRITIS, SYSTEMIC LUPUS ERYTHEMATOSUS, SYSTEMIC SCLEROSIS, SJOGREN SYNDROME, POLYMYOSITIS, AND DERMATOMYOSITIS. MONOZYGOTIC TWINS DISCORDANT FOR ANY DISEASE OFFER AN IDEAL STUDY DESIGN AS THEY ARE MATCHED FOR MANY FACTORS, INCLUDING GENETIC VARIATION AND THIS IS A REAL ADVANTAGE FOR EPIGENETICS STUDY. WE WILL HEREIN DISCUSS THE AVAILABLE DATA IN THE EPIGENETIC DIFFERENCES LEADING TO DISEASE DISCORDANCE IN MZ TWINS FOR SYSTEMIC LUPUS ERYTHEMATOSUS, RHEUMATOID ARTHRITIS, AND SYSTEMIC SCLEROSIS. 2020 18 3871 16 JUVENILE MYELOMONOCYTIC LEUKEMIA - A BONA FIDE RASOPATHY SYNDROME. JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) IS A PEDIATRIC MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASM OVERLAP SYNDROME WITH SUSTAINED PERIPHERAL BLOOD MONOCYTOSIS, AGGRESSIVE FEATURES, AND POOR OUTCOMES. IN >90% OF CASES JMML IS DRIVEN BY GERMLINE OR SOMATIC MUTATIONS INVOLVING THE CANONICAL RAS PATHWAY (PTPN11, NRAS, CBL, KRAS AND NF1), WITH SOMATIC MUTATIONS/ALTERATIONS IN RAS PATHWAY GENES (SECOND HIT), SETBP1, ASXL1 AND JAK3 RESULTING IN DISEASE PROGRESSION. WHILE SPONTANEOUS REGRESSION HAS BEEN SEEN IN GERMLINE PTPN11 AND CBL MUTANT JMML, IN MOST PATIENTS, ALLOGENEIC STEM CELL TRANSPLANT IS THE ONLY CURATIVE MODALITY. JMML SHARES SEVERAL PHENOTYPIC FEATURES WITH ITS ADULT COUNTERPART PROLIFERATIVE, CHRONIC MYELOMONOCYTIC LEUKEMIA (PCMML). PCMML LARGELY OCCURS DUE TO RAS PATHWAY MUTATIONS THAT OCCUR IN THE CONTEXT OF AGE RELATED CLONAL HEMATOPOIESIS (TET2, SRSF2, ASXL1), WHILE JMML IS A BONA FIDE RASOPATHY, WITH ADDITIONAL SOMATIC MUTATIONS, INCLUDING IN EPIGENETIC REGULATORS GENES RESULTING IN DISEASE PROGRESSION. 2020 19 852 33 CHOLANGIOCARCINOMA IN PATIENTS WITH PRIMARY SCLEROSING CHOLANGITIS (PSC): A COMPREHENSIVE REVIEW. CHOLANGIOCARCINOMA (CCA) IS THE MOST COMMON MALIGNANCY IN PATIENTS WITH PRIMARY SCLEROSING CHOLANGITIS (PSC) AND CARRIES A HIGH RATE OF MORTALITY. ALTHOUGH THE PATHOGENESIS OF CCA IN PSC IS LARGELY UNKNOWN, INFLAMMATION-DRIVEN CARCINOGENESIS CONCOMITANT WITH VARIOUS GENETIC AND EPIGENETIC ABNORMALITIES ARE UNDERLYING FACTORS. THE MAJORITY OF CCA CASES DEVELOP FROM A DOMINANT STRICTURE (DS), WHICH IS DEFINED AS A STRICTURE WITH A DIAMETER < 1.5 MM IN THE COMMON BILE DUCT OR < 1.0 MM IN THE HEPATIC DUCT. IN PSC PATIENTS PRESENTING WITH AN ABRUPT AGGRAVATION OF JAUNDICE, PAIN, FATIGUE, PRURITUS, WEIGHT LOSS, OR WORSENING LIVER BIOCHEMISTRIES, CCA SHOULD BE SUSPECTED AND EVALUATED UTILIZING A VARIETY OF DIAGNOSTIC MODALITIES. HOWEVER, EARLY RECOGNITION OF CCA IN PSC REMAINS A MAJOR CHALLENGE. IMPORTANTLY, 30-50% OF CCA IN PSC PATIENTS ARE OBSERVED WITHIN THE FIRST YEAR FOLLOWING THE DIAGNOSIS OF PSC FOLLOWED BY AN ANNUAL INCIDENCE RANGING FROM 0.5 TO 1.5 PER 100 PERSONS, WHICH IS NEARLY 10 TO 1000 TIMES HIGHER THAN THAT IN THE GENERAL POPULATION. CUMULATIVE 5-YEAR, 10-YEAR, AND LIFETIME INCIDENCES ARE 7%, 8-11%, AND 9-20%, RESPECTIVELY. WHEN PSC-ASSOCIATED CCA IS DIAGNOSED, MOST TUMORS ARE UNRESECTABLE, AND NO EFFECTIVE MEDICATIONS ARE AVAILABLE. GIVEN THE POOR THERAPEUTIC OUTCOME, THE SURVEILLANCE AND MANAGEMENT OF PSC PATIENTS WHO ARE AT AN INCREASED RISK OF DEVELOPING CCA ARE OF IMPORTANCE. SUCH PATIENTS INCLUDE OLDER MALES WITH LARGE-DUCT PSC AND POSSIBLY CONCURRENT ULCERATIVE COLITIS. THUS, MORE ATTENTION SHOULD BE PAID TO PATIENTS WITH THESE CLINICAL FEATURES, IN PARTICULAR WITHIN THE FIRST YEAR AFTER PSC DIAGNOSIS. IN CONTRAST, CCA IS LESS FREQUENTLY OBSERVED IN PEDIATRIC OR FEMALE PSC PATIENTS OR IN THOSE WITH SMALL-DUCT PSC OR CONCURRENT CROHN'S DISEASE. RECENTLY, NEW BIOMARKERS SUCH AS ANTIBODIES TO GLYCOPROTEIN 2 HAVE BEEN FOUND TO BE ASSOCIATED WITH AN INCREASED RISK OF DEVELOPING CCA IN PSC. HEREIN, WE REVIEW THE LITERATURE ON THE PATHOGENESIS, INCIDENCE, CLINICAL FEATURES, AND RISK FACTORS, WITH A FOCUS ON VARIOUS DIAGNOSTIC MODALITIES OF PSC-ASSOCIATED CCA. 2020 20 5146 35 POTENTIAL ROLES FOR INFECTIOUS AGENTS IN THE PATHOPHYSIOLOGY OF PRIMARY BILIARY CIRRHOSIS: WHAT'S NEW? PRIMARY BILIARY CIRRHOSIS (PBC) IS A PROGRESSIVE CHOLESTATIC LIVER DISEASE SEROLOGICALLY CHARACTERIZED BY THE PRESENCE OF HIGH-TITER ANTIMITOCHONDRIAL ANTIBODIES AND, HISTOLOGICALLY BY CHRONIC NONSUPPURATIVE CHOLANGITIS AND GRANULOMATA. THE AETIOLOGY OF THE DISEASE REMAINS ELUSIVE, ALTHOUGH GENETIC, EPIGENETIC, ENVIRONMENTAL, AND INFECTIOUS FACTORS HAVE BEEN CONSIDERED IMPORTANT FOR THE INDUCTION OF THE DISEASE IN GENETICALLY PRONE INDIVIDUALS. THE DISEASE SHOWS A STRIKING FEMALE PREDOMINANCE AND BECOMES CLINICALLY OVERT AT THE FOURTH TO SIXTH DECADE. THESE CHARACTERISTICS HAVE PROMPTED INVESTIGATORS TO CONSIDER INFECTIONS THAT PREDOMINATE IN WOMEN AT THESE AGES AS THE LIKELY CANDIDATES FOR TRIGGERING THE DISEASE. RECURRENT URINARY TRACT INFECTIONS DUE TO ESCHERICHIA COLI WERE THE FIRST INFECTIONS TO BE CONSIDERED PATHOGENETICALLY RELEVANT. OVER THE YEARS, SEVERAL OTHER MICROORGANISMS HAVE BEEN LINKED TO THE PATHOGENESIS OF PBC OWING TO EPIDEMIOLOGICAL, IMMUNOLOGICAL, MICROBIOLOGICAL, OR EXPERIMENTAL FINDINGS IN ANIMAL MODELS. RECENT STUDIES HAVE PROVIDED DATA SUPPORTING THE PATHOGENIC ROLE OF NOVOSPHINGOBIUM AROMATICIVORANS AND BETARETROVIRUSES. SEVERAL REPORTS HAVE LINKED OTHER ORGANISMS TO THE INDUCTION OF THE DISEASE AND/OR THE MAINTENANCE OF THE AUTO-AGGRESSIVE RESPONSES THAT ARE PERPETUATED OVER THE COURSE OF THE DISEASE. THIS REVIEW HIGHLIGHTS THE FINDINGS OF THE MOST RECENT STUDIES INVESTIGATING THE LINK BETWEEN INFECTIONS AND PBC. WE ALSO DISCUSS THE CLOSE INTERPLAY OF THE INFECTIOUS AGENTS WITH OTHER ENVIRONMENTAL AND GENETIC FACTORS, WHICH MAY EXPLAIN THE MULTIFACETED NATURE OF THIS PUZZLING DISEASE. 2013