Table 1.

Phenotype and genotype of men used in this study.

Patient	Mean sperm count (×106/ml)	Johnsen score	Testicular histology	Marker defining breakpoint	Ref(s).
BITRA	Azoospermic	2.6	Most tubules contain only Sertoli cells Minority show limited spermatogonial proliferation up to spermatocyte stage, atrophy	sY101 (Del Yq)	31, 32, and M. Kent-First, personal communication
HORIS	Azoospermic	2.2	Similar to BITRA	sY89 (Del Yq)	This work
JOLAR	Azoospermic	2	SCO	sY84–sY86	21
ELTOR	Azoospermic	2	SCO	sY84–sY86	21
SAYER	4.4	7.7	Few tubules contain either only Sertoli cells or spermatogonia, spermatocytes, or spermatids; most contain small to moderate numbers of spermatogonia	sY84–sY87	21
AMGAL	Azoospermic	2	Similar to BITRA	sY84–ND	21
NICKEI	<0.01	6.2	Severely diminished spermatogenesis with partial arrest at the primary spermatocyte and spermatid stage	sY232–sY158	21
HAMIL	0.6	5.1	Most tubules SCO. Minority show spermatogenesis to the spermatozoan stage.	sY152	21
GLIPS	Azoospermic	2	Similar to BITRA	sY153–sY158	This work
H139	Azoospermic	4.9	Pachytene arrest	sY117–Y367/A	13
ER66	Azoospermic	4.6	Pachytene arrest	sY117–Y367/A	This work

STSs were assayed as described by Volrath et al. (2). The pair of markers defining the breakpoint (negative in these patients) are given except for BITRA and HORIS, who have deleted Y chromosomes, which remove the chromosome distal to the breakpoint including the distal heterochromatin, Yqh. Johnsen scores (33) were assessed independently from hematoxylin- and eosin-stained slides. Johnsen scores are a numerical score from 1 to 10 that assess the quality of spermatogenesis, with 10 being full spermatogenesis. ND, not determined; SCO, Sertoli cell only.