Azoospermia Due to a Unique De Novo Balanced Reciprocal Translocation (Y;1) (q12;q25)

A high prevalence of all types of chromosomal abnormalities has been found in male (4.29%) and female (5.88%) partners of infertile couples undergoing intracytoplasmic sperm injection (ICSI) (Morel et al, 2004). Aside from sex chromosome abnormalities (male, 1.82%; female, 4.44%), balanced reciprocal translocations are the most frequently found chromosomal abnormalities (male, 0.98%; female, 0.66%). In ICSI men, the probability of finding a balanced reciprocal translocation has been calculated to be 11.5-times higher than among newborns based on data on 7895 males referred for ICSI and 36 855 newborn males (Morel et al, 2004). Reciprocal translocation is defined as the exchange of chromosomal material between the arms of two heterologous chromosomes, thus changing the order, but usually not the amount of genetic material. Although all chromosomes can be involved in reciprocal translocations, chromosomes 12, 22, and Y are involved more often than expected on the basis of their relative lengths. A balanced reciprocal Y;autosome translocation has been demonstrated between almost every autosome, except chromosome 20 (Hsu, 1994), and even the participation of chromosome 1 seems to be relatively rare in infertile men. To our knowledge, only 10 cases of Y;1 translocation have been published previously (AlAwadi et al, 1985; Moreau et al, 1987; Narahara et al, 1987; Gregori-Romero et al, 1990; Teyssier et al, 1993; Maraschio et al, 1994; Morel et al, 2002, Pabst et al, 2002; Pinho et al, 2005). We present a new variant of a balanced reciprocal (Y;1) translocation associated with azoospermia and we review the literature on this subject.