Characterization of a de novo balanced 1;Y translocation in a phenotypically normal twin male infant.

Objective: To report a translocation between an autosome and the Y chromosome.

Design: Amniocentesis of a fetus because of mother's advanced age followed by karyotype and PCR analysis.

Setting: Tertiary health center.

Patient(s): A phenotypically normal twin male infant.

Intervention(s): Karyotype with G and Q banding and amplification of testis-specific protein 1-Y and of azoospermia factor (AZF) a, AZFb, AZFc, and distal AZFc regions of Y chromosome.

Main Outcome Measure(s): Karyotype, PCR.

Result(s): We report a phenotypically normal twin male infant with de novo 46,ChiY,t(1;Y)(p22;p11) that was found in amniocentesis. In genetic counseling, it was recommended that the fetus be monitored through a detailed prenatal ultrasonographic examination, which did not indicate any pathological findings. A phenotypically normal male baby was born who is now a 12-month-old healthy infant. The karyotype was confirmed in the peripheral blood with G and Q banding. Amplification of testis-specific protein 1-Y, AZFa, AZFb, AZFc, and distal AZFc regions of the Y chromosome did not reveal any deletions.

Conclusion(s): We cannot predict whether this male infant will have oligospermia or azoospermia as an adult and, furthermore, whether in case of fertility there is a risk for unbalanced autosome;Y translocations in the offspring, with congenital malformations and dysmorphic features. This case illustrates the complexities in counseling for prenatally diagnosed de novo autosome;Y translocations and the need for additional cases to be reported.