Genetic Disorders and Biochemical Pathology — Flashcards

Flashcard 191: MEN 4 is due to mutations of _____ gene

Answer: CDKN1B

Flashcard 192: What is the inheritance pattern of Brunner's syndrome?

Answer: X-linked recessive

Flashcard 193: Segawa syndrome is due to the defective _____ enzyme required for BH4 synthesis

Answer: GTP cyclohydrolase I

Flashcard 194: _____ levels of coproporphyrin in urine is seen in Rotor syndrome

Answer: Increased

Flashcard 195: _____ paradox states that risk of expressing mental retardation in fragile X syndrome increases in later generations

Answer: Sherman's

Flashcard 196: Which gene is mutated in congenital cataract?_____

Answer: Crystallin

Flashcard 197: There is impaired synthesis, processing, or ligand binding of _____ in patients of Imerslund-Grasbeck syndrome

Answer: cubilin

Flashcard 198: The mutations contributing to Menieres disease are found in the short arm of chromosome _____.

Answer: 6

Flashcard 199: The ratio of the phenylalanine (Phe) level 2 or 3 hours after a BH4 loading test to the urine _____ level has high sensitivity and specificity for diagnosing Segawa syndrome.

Answer: neopterin

Extra: In Segawa syndrome (GTP cyclohydrolase I deficiency), neopterin production is severely impaired. The ratio of post-load phenylalanine to urinary neopterin is an effective diagnostic marker because phenylalanine levels remain relatively stable (or slightly elevated) while neopterin levels are extremely low.

Flashcard 200: HHH syndrome is caused due to the deficiency of the ornithine _____.

Answer: transporter