A Newborn Is Being Evaluated in the Nursery

question 272

Multiple Choice

A newborn is being evaluated in the nursery.  The patient was born at term via spontaneous vaginal delivery to a 23-year-old woman.  The mother developed dark terminal facial hair and a deepened voice during the pregnancy.  The delivery was unremarkable, and the patient's vital signs are within normal limits.  Examination shows ambiguous genitalia and clitoromegaly.  Laboratory studies reveal elevated serum levels of testosterone and androstenedione.  Karyotype testing shows a 46,XX genotype.  Ultrasound of the pelvis shows a normal-sized uterus.  This infant's presentation is most likely due to deficiency of which of the following enzymes?

• A)5-Alpha reductase
• B)17-Alpha hydroxylase
• C)21-Hydroxylase
• D)Aromatase
• E)HMG-CoA reductase

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Definitions:

Osteoclast

A type of bone cell that breaks down bone tissue, crucial for the development, maintenance, and repair of bones.

Canaliculi

Canaliculi are small, narrow channels or ducts in bone or in the liver, facilitating the transport of nutrients and waste.

Woven Bone

A form of bone characterized by haphazard organization of collagen fibers and is usually formed rapidly during bone formation or repair.

Collagen Fibers

Strong, insoluble protein fibers that form an essential part of the connective tissue in the body, providing tensile strength and elasticity.