Mutations in dynein genes in patients affected by isolated non-syndromic asthenozoospermia.

BACKGROUND: Asthenozoospermia (AZS) is a common cause of male infertility characterized by reduced forward motility (WHO grade A+B sperm motility <50% or A < 25%) or absent sperm motility in fresh ejaculate. AZS may exist as an isolated disorder, in combination with other sperm anomalies or as part of a syndromic association. Up to date, only a few genes, constituting the cilia/flagella structure, have been associated with isolated AZS in humans, whereas several other genes are known to be involved in syndromic form of AZS, including primary ciliary dyskinesia (PCD) and Kartagener syndrome (KS). Axonemal ultrastructural defects, including absent or shortened arms of dyneins, can be found in >50% of PCD/KS patients. Approximately 90% of KS male patients are affected by AZS. The majority of KS patients can be ascribed to dynein genes mutations. METHODS: Mutation screening of DNAI1, DNAH5 and DNAH11 genes was performed in 90 patients with isolated non-syndromic AZS and 200 controls. RESULTS: We found three mutations (one in each gene) specifically associated with AZS in seven patients (7.8%). Mutations are inherited from the mothers and may be found in familial clusters. No ultrastructural axonemal anomaly was detected in sperm. CONCLUSIONS: We report for the first time a possible association between mutations in dynein genes and isolated AZS. Male carriers of the mutations always exhibit AZS, whereas female carriers manifest no alterations in either fertility or pulmonary clearance.

Lack of the T54A polymorphism of the DAZL gene in infertile Italian patients.

The Thr54Ala polymorphism of the deleted-in-azoospermia-like (DAZL) protein has been associated with susceptibility to spermatogenic failure in the Taiwanese population. We used single-strand conformation polymorphism and restriction fragment analyses to investigate the presence of the A-->G transition in exon 3 of the DAZL gene in 95 infertile Italian patients. The patients had oligozoospermia or non-obstructive azoospermia with different degrees of testicular cytological picture. The allele carrying T54A polymorphism was not present in this group of patients nor in 63 controls, indicating that the frequency of this putative mutation is <1% in Italy. Since the Italian population usually shows allelic frequencies similar to the other Caucasian populations, we suggest that the T54A allele might play a role in infertility only in Taiwanese or Asiatic individuals.

Deficiency 10p. Report of a case and exclusion mapping of the hexokinase 1 locus to band 10p11.2.

A patient deficient for most of the short arm of one chromosome 10 is described. The clinical picture is similar to those of other published cases but includes agenesis of olfactory bulbs, an uncommon finding, already noted in few 10p- patients. The normal levels of hexokinase 1 found in the fibroblasts of the patient allow a more precise localization of the gene at band 10p11.2. The results obtained for inorganic pyrophosphatase confirm the data available from two other cases.