Diagnosis: XYY Syndrome

ISCN: 47,XYY

Discussion:
This patient's pediatrician order chromosomes because of this patient's poor academic performance and poor behavior. Like most patients with 47,XYY syndrome, this patient was phenotypically normal. The most common findings in patients with 47,XYY include difficulties with speech (early) and verbal skills, tall stature, poor coordination, and behavioral problems. The behavioral problems often include hyperactivity, temper tantrums (early) and distractability. These patients may have slightly delayed puberty with normal pubertal development and usually normal fertility. The majority of these patients have normal offspring, however, a slightly increased risk for infertility, miscarriage, and chromosomally abnormal offspring has been described.

47,XYY is seen in approximately 1/1,000 newborn males and results from paternal nondisjunction in meiosis II.
As 47,XYY syndrome results from nondisjunction, karyotyping of parents and/or other family members was not recommended. Genetic counseling was recommended to help educate this patient and his family about 47,XYY syndrome.

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