ABGC 100 Genetic Conditions Exam With 100% Correct And Verified Answers

ABGC 100 Genetic Conditions Exam With 100% Correct And Verified Answers T13 - Correct Answer-Nondisjunction; 1 in 12,000 SGA, MCA: hypotelorism, CLP, heart, brain and kidney defects RR is 1% T18 - Correct Answer-Nondisjunction; 1 in 6,000 SGA, MCA: prominent occiput, tightly clenched fingers, heart and brain defects Choroid plexus cyst on u/s RR is 1% T21 - Correct Answer-MATERNAL nondisjunction (90%); 5% translocation 21;**usually 14**; 2% mosaic T21 1 in 800 Hypotonic, heart (50%) and GI defects common Mild to moderate ID Immunodeficiency, leukemia common Adults at risk for EO-AZD RR is 1%; Robertsonian ~15-100% for 21;21 AMA = best documented risk factor 47, XXY (Klinefelter) - Correct Answer-Nondisjunction; may have additional X chr 1/500 - 1/1,000 May fail to develop 2ndary sex characteristics (tx testosterone) Small testes with few or no sperm Learning disabilities Recurrence is rare but may happen Turner - Correct Answer-45,X karyotype due to nondisjunction or loss of a structurally abnormal X or Y Mosaics common, with a cell line containing 46 chr w/ structurally abnormal X or Y 1/3,000 May fail to develop 2ndary sex characteristics Short stature, primary amenorrhea and usually infertile (tx GH and estradiol) Heart (CoA common) and kidney (horseshoe common) Congenital lymphedema with redundant nuchal skin Learning disabilities Recurrence is rare 47, XYY (Jacob's) - Correct Answer-XYY karyotype due to nondisjunction 1 in 1,000 Fertile with LD and behavioral concerns Tall stature Recurrence is rare 47, XXX - Correct Answer-Nondisjunction; some have 3+ X 1 in 1,000 Fertile Cognitive impairment Tall stature Recurrence rare but may happen 22q11.2 (Velo-cardio-facial syndrome, DiGeorge syndrome) - Correct Answer-Microdeletion, transmitted as dominant trait **90% de novo, 3Mb common deletion** 1/4,000 - 1/6,000 CP (**NO CL**), conotruncal cardiac malformations, Absence of parathyroids (**HYPOcalcemia**) **Thymus aplasia (immunodeficiency)** LD and psychiatric disorders Germline mosaicism possible Prader-Willi syndrome - Correct Answer-Genomic imprinting disorder 70% Deletion of the paternal 15q11.2-q13 region 25% Maternal UPD of chr 15 5% Mutation of the imprinting center on chr 15 **Causative gene(s) NOT known** 1/10,000 - 1/25,000 At birth: hypotonic, FTT Childhood: hyperphagia, short stature (tx with GH), obesity, DD and behavioral concerns Recurrence is rare Angelman syndrome - Correct Answer-Genomic imprinting disorder 68% Deletion of the maternal 15q11.2-q13 region 11% **UBE3A** gene mutation (AD) 7% Paternal UPD of chr 15 3% Small imprinting region deletions (AD) 1/12,000 - 1/20,000 Severe DD, seizures, hyperactivity, abnormal gait Recurrence is rare Williams syndrome (Williams-Bueren syndrome) - Correct Answer-Microdeletion of chromosome **7q**11.2 ***Deletion of elastin gene*** 1 in 7,500 Often born POST-term, SGA and FTT Neonatal **HYPER-calcemia** **Supravalvar aortic stenosis (SVAS)**