Ring Y chromosome: 45,X/46,X,r(Y) chromosome mosaicism in a phenotypically normal male with azoospermia

The role of Y chromosome deletions in male infertility

“…Although it had been observed that deletions of the long arm of the Y chromosome could result in breakdown in spermatogenesis, leading to infertility in humans (79,80), it was not recognized until 1976 when Tiepolo & Zuffardi (62) published their findings that the long arm of the Y chromosome carried genetic information essential for spermatogenesis. In the six azoospermic men studied, they found that all of these males carried a deletion of all the distal heterochromatin of the long arm of the Y chromosome (Yq) and that azoospermia was the only symptom presented.…”

Minute chromosomes replacing the Y chromosome carry Y‐specific sequences by restriction fragment analysis and in situ hybridization

“…This, as well as reports of numerical Y aberrations [Nielsen et al, 1971;Varrela, 1984;Varrela et al, 1984a,b] have suggested that the Y chromosome contains height controlling gene(s): Patients with ring Y or Y-derived minute chromosomes have been reported with normal height [patient 1 of this study; Mattei et al, 1979 (observation 3); Madan et al, 1979 (patient 2)] or with short stature [German et al, 1973;Langmaid and Laurence, 1974;Wilson et al, 1976;Maeda et al, 1976;Steinbach et al, 19791. However, the extent of the deletions on both short and long arms of ring Y or Y-derived minute chromosomes have not been characterized sufficiently by cytogenetic staining methods to correlate growth promoting gene(s) with regions lost in the Y chromosome.…”

“…In four of six cases mosaicism for a ring Y chromosome was present. These were phenotypically normal males with azoospermia who were ascertained because of infertility, as was patient 1 in our study [Chandley and Edmond, 1971;Chandley et al, 1975;Maeda et al, 1976;Steinbach et al, 1979;Madan et al, 19791. Mosaicism was not detected in two other males.…”

“…Only 3 % of cells reached meiosis 11. Testicular biopsies and meiotic studies in infertile males with other structurally abnormal Y chromosomes have presented essentially the same results, an arrest in meiosis I, leading to oligospermia or azoospermia [Lopez Pajares et al, 1979;Gonzales et al, 1981;ViguiC et al, 19821 or total absence of spermatogenesis [Maeda et al, 1976;Yunis et al, 19771. Thus, the mechanism responsible for azoospermia in phenotypically normal males with structural abnormalities of the Y chromosome may be the inability of the X and the abnormal Y chromosome to pair normally rather than deletion of hypothetical gene(s) on the Y long arm that code for a fertility factor. This would also explain why males with reciprocal Y/autosome translocations and breaks either in band Yqll or Yq12 and males with duplications of Yq are azoospermic, while males with a complete loss of the distal band (Yq12) can be fertile.…”

Identification and comparison of chromosomal alterations in infertile and fertile males of Tamil Nadu region exposed to cigarette smoking

“…Studies have indicated that deletions on the long arm of Y chromosome involving a particular and consistent segment might lead to azoospermia and sometimes to severe oligozoospermia (Reijo et al 1996). It has been observed that deletions of the long arm of the Y chromosome could result in breakdown in spermatogenesis, leading to infertility in humans (Maeda et al 1976). In fact, deletion screening of the Y chromosome is now considered as standard practices for patients with sever oligozoospermic and azoospermic conditions undergoing assisted reproduction in most countries in the world.…”