A putative human male infertility gene DAZLA: genomic structure and methylation status

The DAZLA (DAZ Like Autosomal) gene on human chromosome 3 shares a highdegree of homology with the DAZ (Deleted in AZoospermia) gene family on theY chromosome, a gene family frequently deleted in males with azoospermia orsevere oligospermia. The involvement of both DAZ and DAZLA inspermatogenesis is suggested by their testis-specific expression and theirhomology with a Drosophila male infertility gene, boule. Whereas maleinfertility resulting from deletion of the DAZ genes on the Y chromosomeoccurs sporadically, that due to a defective DAZLA gene is expected to beinheritable. The fraction of males with idiopathic azoospermia oroligospermia that harbour mutations in the DAZLA gene remains unknown. As aprerequisite for mutation screening, the genomic structure of the DAZLAgene was elucidated and found to consist of 11 exons spanning 19 kh. Theexon/intron boundaries are conserved between DAZ and DAZLA. The 5' end ofboth genes are hypomethylated in spermatozoa but not in leukocytes orplacenta, consistent with the expression pattern of the genes. The genomicstructure of DAZLA paves the way for mutation detection in families withautosomal recessive male infertility.