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Diagnosis: Klinefelter
Syndrome
ISCN: 47,XXY
Discussion:
As many of the findings of Klinefelter syndrome are mild, many patients
are not diagnosed until during or after puberty. In this case, the patient
and his wife sought help because of infertility. Careful clinical inspection
revealed small testicles, poor secondary sexual characteristics and tall
stature, findings suspicious for Klinefelter syndrome. Some of the most
common findings in patients with Klinefelter syndrome include tall stature
with long limbs, small testicles, gynecomastia, poor virilization at puberty,
infertility, a slight decrease in IQ when compared to siblings, behavioral
problems, and learning disabilities. Patients with Klinefelter syndrome
are at an increased risk for breast cancer and mediastinal germ cell tumors.
Klinefelter syndrome is seen in about 1/500 males. Approximately half
of the cases are caused by maternal meiotic nondisjunction, and about
half of the cases are caused by paternal meiotic nondisjunction. Approximately
10% of cases are mosaics (mos47,XXY/46,XY) and are caused by mitotic nondisjunction;
these patients often have a milder phenotype.
As Klinefelter syndrome results from nondisjunction, karyotyping of parents
and/or other family members was not indicated. Genetic counseling was
recommended to help educated this patient and his wife about Klinefelter
syndrome.
Web Links:
Additional information can be obtained at The
Turner Center web site, the 47,XXY
site, and the Klinefelter
Syndrome Support Group Home Page.
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