1990
A couple comes to the clinic for preconception counseling. They are offered genetic screening because they are of Ashkenazi Jewish descent. Test results show that both are carriers for a lysosomal enzyme deficiency disorder that results in decreased metabolic degradation of a phospholipid substrate to ceramide, which leads to a buildup of the phospholipid. They are counseled about the chance that their offspring will be affected by this disorder. The couple wants to know the clinical features of an affected child. Which of the following findings would be most consistent with this condition?
A.Abnormally shaped bones and corneal clouding
B.Coarse facial features and cardiac dysfunction
C.Neuropathic pain and angiokeratomas
D.Retinal opacification and splenomegaly
E.Small stature and infertility
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THE CORRECT ANSWER IS : D.
Retinal opacification and splenomegaly
(43%)
EXPLANATION
ss sphingomyelin results in cells that appear enlarged, foamy, and vacuolated on electron microscopy. These lipid-laden foam cells accumulate in the liver (hepatomegaly), spleen (splenomegaly), and CNS (hypotonia, neurodegeneration). After a period of normal development, affected infants do not attain new skills and regress from previously acquired milestones (eg, sitting with support, head control, social smile). Accumulation of sphingomyelin in the retinal ganglion cells also leads to retinal opacification, which gives the appearance of a cherry-red macula. Disease is progressive, and death usually occurs by age 3.
Niemann-Pick disease, like several other rare genetic disorders (eg, Tay-Sachs disease, Gaucher disease, Bloom syndrome), is more common in the Ashkenazi Jewish population than in the general population. The increased risk for rare and often life-threatening genetic mutations is attributed to the founder effect, or the loss of genetic variability within a group that historically conceived within their own community. An Ashkenazi Jewish couple should be offered genetic counseling and testing befor
