A child presents with rapidly progressive hearing loss and thyroid enlargement, and genetic testing identifies a variant in SLC26A4. What concept describes a single gene causing multiple, apparently unrelated phenotypes?
A 5-year-old girl is brought to clinic for developmental delay and distinctive facial features. Chromosomal microarray analysis reveals a 1.5 Mbp deletion on chromosome 22q11. Which test most efficiently confirms the diagnosis in this patient?
A 6-year-old presents with syndactyly, hypothalamic hamartoma, and polydactyly. Genetic testing identifies a mutation in GLI3. Which syndrome does this likely represent?
A 2-week-old girl is found to have jaundice and progressive deafness after treatment with gentamicin. Genetic analysis identifies a homoplasmic m.1555A>G pathogenic variant. Through whom was this mutation inherited?
A 6-week-old infant presents with microcephaly, postaxial polydactyly, and 2-3 toe syndactyly, along with poor feeding and hypotonia. Cholesterol level is low, and 7-dehydrocholesterol is markedly elevated. Genetic testing identifies a pathogenic mutation in DHCR7. Which syndrome does this likely represent?
A 6-year-old boy presents with severe growth deficiency and radial ray anomalies. Pancytopenia is noted on labs, and chromosomal breakage studies are positive. What is the most likely underlying defect?
A 9-year-old boy presents with a broad forehead, hypertelorism, a triangular facies, and cholestatic jaundice with pruritus. DNA testing demonstrates a pathogenic variant in JAG1. What pathway is most directly implicated in his disorder?
A 3-year-old girl is evaluated for short stature, broad chest, lymphedema, and coarctation of the aorta. Which chromosomal process most likely led to her condition?
