A 6-month-old girl of Ashkenazi Jewish descent is brought to the pediatrician due to parental concerns about her development. The parents report that she was previously able to roll over and reach for objects, but she has lost these abilities over the past month. Physical examination reveals hypotonia, a protuberant abdomen with palpable hepatosplenomegaly, and decreased deep tendon reflexes. Funduscopic examination demonstrates a bilateral cherry-red spot on the macula. Which of the following enzymes is most likely deficient in this patient?
- SphingomyelinaseCevap
- BHexosaminidase A
- CGlucocerebrosidase
- DAlpha-galactosidase A
- EGalactocerebrosidase
Cevap
Sphingomyelinase
The patient's presentation of developmental regression, a cherry-red macula, and hepatosplenomegaly is the classic triad for Niemann-Pick disease type A. This autosomal recessive lysosomal storage disorder is caused by a deficiency of the enzyme sphingomyelinase, leading to the accumulation of sphingomyelin in macrophages (resulting in foam cells) and various tissues, including the liver, spleen, and central nervous system.
Adım Adım Çözüm
Anahtar Kavram
Niemann-Pick disease type A is an autosomal recessive lysosomal storage disorder caused by sphingomyelinase deficiency, classically presenting in infancy with developmental regression, hepatosplenomegaly, and a cherry-red macula.