Abgc Exam 2024 (Graded A+)

Holt-Oram Syndrome correct answers TBX5, AD, high penetrance, 1/3 de novo Upper limb defects (preaxial radial ray anomaly: radial, carpal and ulnar bones), congenital heart malformation (mostly Secundum atrial septal defect) and conduction disease. Refer to cardio, orthopedist, hand surgeon. Hereditary Hemorrhagic Telangiectasia correct answers AD, LOF mutations in ENG (40-60%), ACVRL1 (25-55%), or SMAD4 (1-2%), or GDF2 (rare). SMAD4 mutations can also cause Juvenile Polyposis Syndrome. Large AVMs can present in the lungs, liver, and brain. telangiectases in oral/nasal cavity, lips, face, chest, and fingers, usually onset in late teens. Frequent epistaxis: 95%, onset at 12yo. GI bleeding: 25%, usually onset after 50yo Brugada syndrome correct answers AD, 23 genes, usually LOF in SMAD4. only 1% de novo. Cardiac conduction abnormality, can cause syncope, V fib, cardiac arrest, sudden death (SIDS or SUNDS). Most common in SE Asians. Factor V Leiden correct answers Most common inherited thrombophilia: 3-8% US/EU pop are hets (homos at higher risk of VTEs). AD, c.1691GA variant in F5 gene - factor V not cleaved by Activated Protein C - poor coagulation. Incomplete penetrance. Clin feat: venous thromboembolism (eg DVT), PE, esp during preg. Hemophilia A correct answers X-linked, F8 gene. Deficiency in factor VIII (8) clotting activity - slow coagulation, prolonged bleeding. 100% penetrant in males. 30% of female hets have low clotting activity (40%) - at risk of bleeding. Clin feat: low factor VIII clotting activity in presence of normal von Willebrand factor level, prolonged aPTT, normal PT. Severe: 1% factor VIII, dx by 2yo. spontaneous joint bleeds (hemarthrosis), bleeding from mouth injuries, spontaneous deep-muscle bleeds/hematomas. Moderate: dx by 6yo, rarely spont bleeds, prolonged oozing. Mild: dx later in life after surgery/trauma, no spont bleeds, abnormal bleeding with surgery. Hemophilia B correct answers X-linked, F9 gene. Deficiency of factor IX (9) clotting activity - prolonged oozing after injuries, tooth extractions, or surgery, and delayed or recurrent bleeding. Less prevalent than Hemophilia A. Severity scale similar to Hemo A. Hereditary Hemochromatosis correct answers AR, HFE gene - Inappropriately high absorption of iron by small intestine. Low penetrance: 75%-90% of individuals with HFE hemochromatosis are asymptomatic.