[Genetic analysis of a child with mental retardation and hypospadia].

To carry out genetic testing for a boy presenting with mental retardation and hypoplasia.Conventional karyotyping, fluorescence in situ hybridization (FISH) and single nucleotide polymorphism based array (SNP-array) were used to analyze the boy and his parents.SNP-array has detected a 25.7 Mb microduplication at 2q33.3q36.3 in the boy. Chromosomal karyotyping and FISH analysis indicated that his mother had a karyotype of 46,XX,ish ins(11;2) (p15;q33q36), and that the boy has carried an abnormal chromosome 11 derived from the maternal translocation. The karyotype of the boy was ascertained as 46,XY,ish der(11)ins(11;2) (p15;q33q36)mat.SNP-array combined with G-banding and FISH can delineate the cryptic translocation and is valuable for the assessment of recurrence risk for subsequent pregnancies.