OBJECTIVETo report a rare family of AZFc deletion with natural transmission and explore the potential mechanism by which identical microdeletions cause different phenotypes.

METHODSChromosomal quantity and construction were detected by G-band, Y-chromosomal microdeletions by multiple PCR amplification for 12 sequence tagged sites (STSs, and the single-nucleotide polymorphisms (SNPs) of the DAZL gene, the autosomal homologue of deleted-in-azoospermia (DAZ) gene by DNA sequencing.

RESULTSChromosome analysis revealed a normal karyotype 46, XY in the father and both of his two sons and microdeletions of the full AZFc region were identical, including sY152, sY157, sY242, sY254, sY255, sY239 locus. However, the phenotypes of the affected patients were different: the father had normal fertility, but the sperm density of his two sons deteriorated age-dependently, and the younger one suffered from left cryptorchidism. SNP analysis demonstrated that two polymorphisms in exon 2 and 3 of the DAZL gene were identical in both the father and his sons.

CONCLUSIONIdentical Y-chromosomal microdeletions causing different phenotypes in this family is not associated with the polymorphisms of DAZL gene and may be related to other genes or environmental factors.