Turner Syndrome with Isochromosome Xq and Familial Reciprocal Translocation t(4;16)(p15.2;p13.1)

We present here a 16-year-old Turner syndrome patient with a complex karyotype that includes a maternally-inherited balanced translocation between chromosomes 4 and 16 and mosaicism of the isochromosome Xq10. Her karyotype was 45,X,t(4;16) (p15.2;p13.1)[9]/46,X,i(X) (q10),t(4;16)(p15.2;p13.1) [91]. The karyotype of her father was normal, whereas that of her mother had the same balanced translocation and numerical abnormalities of chromosome X and was designated as 45,X,t(4;16)(p15.2;p13.1) [2]/46,XX,t(4;16)(p15.2;p13.1)[93]/47,XXX,t(4;16) (p15.2; p13.1)[5]. The two siblings of the patient also had the same reciprocal translocation. We consider this to be the first such patient with an inherited reciprocal translocation and structural abnormality of the X chromosome (isochromosome Xq).