Fluorescence In Situ Hybridization Studies of Sperm Aneuploidies in Infertile Men

Abstract

Fluorescence in situ hybridization analysis, performed with chromosome specific DNA probes labeled with fluorochromes, is a simple and reliable tool for the indirect study of aneuploidies in interphase cells such as spermatozoa. It is known that infertile male patients with poor sperm quality, due to different causes, produce cytogenetically abnormal spermatozoa despite a normal constitutional karyotype as a result of an altered intra-testicular environment that negatively affects the mechanisms controlling chromosome segregation during cell division. A particular subgroup of this category is composed of individuals with systematic sperm defects, characterized by an identical, specific alteration that affects the vast majority of their sperm population. Altered meiotic segregation has been described mainly in globozoospermia and in sperm with dysplasia of the fibrous sheath. Moreover, we also considered sperm aneuploidies in the presence of somatic chromosome abnormalities: numerical chromosomal anomalies, such as the presence of an extra chromosome and structural chromosomal anomalies, including translocations and inversions. It is known that somatic chromosomal abnormalities are often associated with infertility and have definite consequences on the cytogenetic anomalies observed in spermatozoa. Since individuals with abnormal semen parameters, also those that are carriers of a constitutional abnormal karyotype, make up the majority of intracytoplasmic sperm injection candidates, it is of great interest to study the chromosomal constitution of their spermatozoa. The problem of the possible presence of aneuploidy in sperm from infertile men should be seriously considered due to the documented risk of the transmission of a chromosomal imbalance to offspring.