Genetic study of a child carrying a maternally derived unbalanced 46,Y,der(X)t(X;Y)(p22;q11) chromosomal translocation

Objective: To explore the genetic basis for a child featuring short stature, saddle nose, cryptorchidism and mental retardation.

Methods: The child and his parents were subjected to G-banded karyotyping and chromosomal microarray analysis (CMA).

Results: The child was found to have a 46,Y,der(X)t(X;Y)(p22;q11)mat karyotype. CMA has revealed a 8.3 Mb deletion at Xp22.33p22.31 and a 43.3 Mb duplication at Yq11.221qter. His mother had a karyotype of 46,X,der(X)t(X;Y)(p22;q11). His father had a normal karyotype.

Conclusions: The child has carried an unbalanced translocation der(X)t(X;Y) (p22;q11) derived from his mother. His clinical phenotype has correlated with the size and position of X chromosome deletion. Compared with the females, abnormal phenotypes such as mental retardation and growth retardation of male carriers are more severe.