Hereditary aromatase deficiency is a rare disorder resulting in estrogen deficiency and androgen excess. An affected male may show a number of clinical findings.


Inheritance: autosomal recessive


Affected gene: CYP19A1

Affected enzyme: aromatase cytochrome P450 (P450arom)

Consequence of mutation: defect in the final step in the conversion of C19 steroids to estrogens, resulting in low estrogen and high androgen levels


Clinical features:

(1) delayed epiphyseal closure/fusion with delayed bone age

(2) tall stature with a eunuchoid body habitus, starting with puberty

(3) osteopenia and osteoporosis with recurrent bone fractures

(4) bone pain

(5) variable abnormalities of testicular size (including macroorchidism)


Laboratory findings:

(1) no excess in growth hormone

(2) high normal or elevated serum testosterone

(3) high normal or elevated gonadotropins (FSH, LH)

(4) low serum estrogens

(5) variable defect in spermatogenesis


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