Molecular Cytogenetic Characterization of an inv(Y)(p11.2q11.221∼q11.222) in a Syrian Family

Abstract

Constitutional chromosomal abnormalities are an important cause of miscarriage, infertility, congenital anomalies and mental retardation in humans. Pericentric inversions of the human Y-chromosome [inv(Y)] are rather common and show an estimated incidence of 0.6-1:1,000 in males in the general population. Most of the reported cases with inv(Y) are familial. For carriers of pericentric inversions the risk of mental retardation or multiple abortions is not apparently increased and there is no relation with abnormal phenotypic features. Polymerase chain reaction (PCR) analysis to detect microdeletions along the Y-chromosome as well as cytogenetic and fluorescence in situ hybridization (FISH) analysis were done to delineate the characteristics of an inv(Y) in a Syrian family. Thus, we present a detailed molecular-cytogenetic characterization of a father and his two sons having an inv(Y)(p11. 2q11.221∼q11.222) with varying mental retardation features but otherwise normal phenotype.

Keywords: Ampli-conic fertility genes; Fluorescence in situ hybridization (FISH); Inversion; Mental retardation; Y-Chromosome.

Figure 1.

Karyotype from a peripheral blood meta-phase of the one of the three patients showing 46,X, der(Y).

Figure 2.

Centromeric probe for the Y-chromosome and centromere-near probes derived from Yq and Yp revealed the breakpoints of the pericentric inversion as Yp11.2 and Yq11.221∼q11.222; the FISH results are depicted in A. B Schematic drawings of a normal and the derivative Y-chromosome are shown.