A 10-year-old boy is brought to the physician because of a 1-week history of fatigue. He recently recovered from a cold. Physical examination shows scleral icterus. Laboratory studies show:
Hemoglobin: 10.4 g/dL
Hematocrit: 31.2%
MCV: 92 fL
Direct antiglobulin test: Positive
A blood smear is performed and shows spherocytes.
Genetic testing is most likely to show which of the following?
Heterozygosity in the spectrin gene
Heterozygosity in the α-globin gene
Heterozygosity in the β-globin gene
Homozygosity in the spectrin gene
Homozygosity in the α-globin gene
Homozygosity in the β-globin gene
No specific mutation
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Cut-to-the-chase Answer (1:05):
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HY USMLE Answer (5:51):
