A 2-year-old boy has a congenital disorder associated with hypotonia, lactic acidosis, optic atrophy, neurosensory hearing impairment, and seizures. He has a 4-year-old sister with myoclonus and hypotonia. A muscle biopsy is performed and shown below.
Which of the following is most likely characteristic of this patient’s disorder?
Heteroplasmy
Imprinting (maternal)
Imprinting (paternal)
Incomplete penetrance
Pleiotropy
Variable expressivity
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Cut-to-the-chase Answer (0:53):
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HY USMLE Answer (12:13):
