Interstitial 4q Deletion and Isodicentric Y-Chromosome in a Patient with Dysmorphic Features

Abstract

We present a 2-year-old boy with a de novo 46,XY,idic(Y)(q11.221),del(4)(q26q31.1) karyotype. G-banding, FISH, MLPA, and SNP-array techniques were used to characterize the 24-Mb deletion in 4q and the breakpoint in the isodicentric Y-chromosome region between 15,982,252 and 15,989,842 bp. The patient presented with mild facial dysmorphism, hemangioma, mild frontal cerebral atrophy, and Dandy-Walker variant. Essentially, this case reveals that patients can present more complex genomic imbalances than initially suspected.

Fig. 1

A Patient at the age of 14 months. B Partial karyotype of the patient showing the del(4)(q26q31.1) and the idic(Y)(q11.221). C Partial karyotype of his father showing chromosome pair 4 and the Y-chromosome. D Array images of the patient's Y-chromosome showing the duplicated region (blue) and the missing region (red). E Chromosome 4 showing the deleted region (red). F FISH with a centromeric probe for the Y-chromosome showing 2 hybridization signals (arrow) on an interphase nucleus. G An SRY gene probe showing 2 signals on the idic(Y). H FISH with the RP11-669F13 probe, showing a signal only on the normal chromosome 4.