Should Know Study Set for ABGC Boards Exam Questions and Answers

Should Know Study Set for ABGC Boards Exam Questions and Answers Angelman Syndrome causes (expression and % of total) - ANSWER -**paternal imprinting defect, should be maternal expression 5-7 kb deletion on maternal chr15q11.2-13 (60-70%) UBE3A maternal deletion (11%) Paternal UPD15 (3-7%) Angelman testing strategy and condition features - ANSWER -methylation first since finds ~80% of cases then UBE3A seq and del/dup features: happy demeanor, abnormal gait, seizures, delayed/absent speech Prader-Willi Syndrome causes (expression and % of total) - ANSWER -**maternal imprinting defect, should be paternal expression of region 5-6 kb deletion on paternal chr15q11.2-13 (60-70%) Deletion involves SNRPN gene Maternal UPD15 (20-30%) PWS testing strategy and condition features - ANSWER -Methylation will detect 99% 2 | P a g e Created by Grace Amelia © 2025, All Rights Reserved. Features: hypotonia, FTT, obesity, hyperphagia, small hands and feet, DD Angelman and Prader-Willi pneumonic devices - ANSWER -Moms are Angels = should have maternal expression of the region therefore PWS is in a region that typically has paternal expression Beckwith-Wiedemann syndrome causes (imprinting and % breakdown) - ANSWER -**paternal imprinting, maternally expressed Sporadic (85%) Loss of methylation on maternal chr11p15.5 IC2 (50%) Paternal UPD11 (7-10%) Gain of methylation on maternal chr11p15.5 IC1 (5%) Maternal CDKN1C deletion (40% w/ family hx, 5% w/o) also KCNQ1 gene Beckwith-Wiedemann syndrome testing strategy and condition features - ANSWER -Order methylation first, then CDKN1C sequencing and del/dup Features: overgrowth, macroglossia, omphalocele, ear pits, Wilms tumor Russell-Silver syndrome causes (imprinting and % breakdown) - ANSWER -*maternal imprinting, paternal expression Loss of methylation on paternal chr11p15.5 IC1 (35-50%) 3 | P a g e Created by Grace Amelia © 2025, All Rights Reserved. Maternal UPD7 (10%) Russell-Silver testing strategy and condition features - ANSWER -Order methylation first, then UPD studies Features: triangular facies, IUGR, poor post-natal growth, short stature, body asymmetry causes and implications of cystic placenta - ANSWER -Partial molar pregnancy- triploidy Triploidy is incompatible with life High risk First trimester screen for T21 values (high or low) - ANSWER -high hCG, low PAPP-A (know what MoM curve looks like for all screen results too) High risk First trimester screen for T18 values (high or low) - ANSWER -low hCG, low PAPP-A High risk Second trimester screen for T21 values (high or low) - ANSWER -high hCG, high inhibin-A, low AFP, low uE3 High risk Second trimester screen for T18 values (high or low) - ANSWER -low hCG, low AFP, low uE3 Genotype of Partial mole? - ANSWER -triploidy (digyny- 69, XXX or diandry- 69 XXY) Genotype of complete hydatidiform mole? - ANSWER -paternal UPD of all chromosomes Genotype of ovarian teratoma? - ANSWER -maternal UPD of all chromosomes 4 | P a g e Created by Grace Amelia © 2025, All Rights Reserved. Testing strategy/what will be found for cystic fibrosis dx - ANSWER -Elevated trypsinogen on NBS followed by genetic mutation analysis (most NBS is genotyping) **Gold standard: Confirm w/ sweat test elevated 60 u/L genetic testing: if 1 variant - do del/dup (possibility for UPD) and if no variants found possibly other disorder Testing strategy/what will be found for sickle cell dx - ANSWER -Hemoglobin electrophoresis, genetic testing not necessary Will see elevated HbS Testing strategy/what will be found for FAOD (fatty acid oxidation) dx - ANSWER -acylcarnitine profile, PAA (phenylalanine deaminase test), UOA Testing strategy/what will be found for maple syrup urine disease (MSUD) dx - ANSWER -PAA- elevated leucine, isoleucine, valine Testing strategy/ % breakdown for MECP2 disorders (Rett) - ANSWER -Sequencing (80%) then del/dup (8%) Testing strategy/what will be found for homocystinuria dx - ANSWER -PAA- elevated methionine, homocysteine Testing strategy/what will be found for PKU dx - ANSWER -PAA- elevated phenylalanine Testing strategy/what will be found for tyrosinemia dx - ANSWER -PAA- elevated succinylaceton