Hypoplastic external genitalia in association with X;autosome chromosome translocation.

STUDY OBJECTIVE: To learn the relationship between X;autosome chromosome translocation and hypoplastic external genitalia. BACKGROUND: An X;autosome translocation usually presents with phenotypic features similar to Turner syndrome. PARTICIPANTS: We present three female siblings and their mother with X;autosome translocation and hypoplastic external genitalia. METHODS: Case presentation. RESULTS: Three female siblings, ages 14, 16, and 18 years, presented for routine checkup. All had been seen in the past for short stature, learning disability, and other features similar to those seen in Turner syndrome. At time of presentation, all three had primary amenorrhea. On genital exam, each was found to have hypoplastic external genitalia with absent clitoris and labia minora. Pelvic ultrasound in all subjects showed normal but prepubertal uterus and ovaries. Two subjects have unbalanced translocations with karyotype 46,X,der(9)t(9;X)(q11.2;q22.3). This abnormal chromosome complement results in the loss of the short arm of the X chromosome and the gain of an extra copy of the long arm of chromosome 9. The third subject and her mother have balanced translocations with the karyotype 46,X,t(9;X)(q11.2;q22.3). X-inactivation studies showed skewed inactivation of the normal X chromosome in the balanced translocation carriers, while the two girls with the unbalanced karyotype had skewed inactivation of the translocation product. All subjects have growth hormone deficiency. The oldest sibling was able to menstruate regularly after estrogen/progesterone therapy. The other two patients are currently receiving growth hormone and are gaining height. CONCLUSION: X;autosome translocations may be associated with hypoplastic external genitalia but normal internal genitalia. Balanced carriers can be fertile. To our knowledge, the presence of hypoplastic external genitalia in association with X;autosome translocation has not been previously reported. This should be added to the possible causes of hypoplastic external genitalia