patho #4 - belkin

[ArchivalUser]

A 5-year-old boy is identified with mental impairment, downward dislocation of the lenses, mild scoliosis, pectus excavatum, and arachnodactyly. Increased levels of homocystine are identified in his urine. What gene is most likely mutated in this child?


A. Branched chain ketoacid decarboxylase (BCKD)
B. Collagen type I
C. Connexin 43 (Cx43)
D. Cystathionine beta synthetase
E. Fibrillin

[ArchivalUser]

no idea D????

[ArchivalUser]

d.

[ArchivalUser]

E.Marfan syndrome?

[ArchivalUser]

D.

[ArchivalUser]

Option D (Cystathionine beta synthetase) is correct. An increased level of homocystine is the hallmark of homocystinuria, most often caused by a deficiency of cystathionine beta synthetase. It is often confused with Marfan syndrome because of an overlap in some symptoms, but elevated homocystine is not a feature of Marfan. Lens dislocation is generally upward in Marfan syndrome.