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An 11-month-old infant is being worked up for failure to thrive. The infant has failed to gain weight appropriately and is developmentally delayed. Physical exam is significant for the presence of bilateral cherry-red macular spots and hepatosplenomegaly. Which of the following would most likely be elevated in this patient?
A. Glycogen
B. GM2 gangliosides
C. Phenylalanine
D. Homogentisic acid
E. Sphingomyelin
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Ans B GM2 gangliosides Tays-Sachs disease
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mia87, there is a clue to make answer B wrong, plz read again b4 I post the answer
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Yes, okt3 the ans is E Niemann-Pick disease by the hepatosplenomegaly and failure to thrive and nervous system deterioration. I didnt read the question properly thanks for pointing it out.
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Choice (E) is the correct answer. Type A Niemann-Pick disease is lysosomal storage disease caused by a deficiency of the enzyme sphingomyelinase and leads to toxic accumulation of sphingomyelin. Infants born with type A Niemann-Pick disease are normal in appearance. Hepatosplenomegaly develops, along with failure to thrive and progressive neurological deterioration. Many patients with Niemann-Pick disease also have cherry-red macular spots that are also seen in Tay-Sachs disease. Death usually results at 2-4 years of age. Abnormal metabolism of glycogen (Choice A) results in glycogen storage diseases. Examples of glycogen storage diseases include Von Gierke's disease, Pompe's disease, Cori's disease, and McArdle's syndrome Tay-Sachs disease is an autosomal recessive gangliosidosis caused by a deficiency of the enzyme hexosaminidase A. GM2 gangliosides (Choice B) accumulate in neurons and cause disruption of the central nervous system. The disease is prevalent among Ashkenazi Jews. Characteristic findings include mental retardation, blindness, and a cherry red spot on the macula. Phenylketonuria (PKU) is a hereditary condition caused by a deficiency of phenylalanine hydroxylase. Phenylalanine hydroxylase catalyzes the conversion of phenylalanine to tyrosine in the liver. In PKU, tyrosine becomes an essential amino acid. Phenylalanine (Choice C) accumulates and causes progressive central nervous system demyelination and neurologic deterioration. Patients with PKU usually have blond hair, are blue-eyed and have a characteristic musty odor. Treatment is early dietary restriction of phenylalanine intake. Homogentisic acid (Choice D) accumulation is caused by alkaptonuria, also known as black urine disease, which is a disease caused by a deficiency of homogentisic oxidase. Homogentisic acid is a toxic byproduct of tyrosine catabolism and is harmful to bones and cartilage. It is excreted in the urine, and patients with alkaptonuria have urine that turns black on standing. Patients also develop debilitating arthritis, known as ochronosis arthritis. Ochronosis refers to the dark pigmentation of cartilage and fibrous tissue that is seen in alkaptonuria as a result of homogentisic acid accumulation. .
