POSTER ABSTRACTS / RESUMOS DE POSTERS

 

P-11

Mutation analysis of genes involved in sperm motility: a study in patients with total sperm immotility

 

 

Rute Pereira^I,II; Jorge Oliveira^III; Rosário Santos^III; Ângela Alves^II; Elsa Oliveira^II; Luís Ferraz^IV; Alberto Barros^V; Mário Sousa^II

^IDepartamento de Biologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
^IIDepartamento de Microscopia, Laboratório de Biologia Celular, Instituto de Ciências Biomédicas de Abel Salazar, UMIB-FCT, Universidade do Porto, Porto, Portugal
^IIIUnidade de Genética Molecular, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto E.P.E., Porto, Portugal
^IVDepartamento de Urologia, Centro Hospitalar de Vila Nova de Gaia E.P.E., Vila Nova de Gaia, Portugal
^VCentro de Genética da Reprodução Prof. Alberto Barros, Porto, Portugal

ruterpereira@gmail.com

 

 

Reduced sperm motility represents one of the major male causes of infertility. The axoneme (Ax) is the flagellar motor of the sperm cell and several mutations in genes involved in the assembly and regulation of the Ax have been proved to be responsible for certain cases of infertility associated with severe sperm immotility. For instance, mutations in the genes CCDC39, CCDC40 (that are involved in assembly of the dynein regulatory complex and the inner dynein arm complex), DNAI1 and DNAH5 (that are involved in the assembly of outer dynein arms) are associated with primary ciliary dyskinesia (PCD). PCD is an inherited autosomal recessive genetic disorder whose typical diagnostic features include the absence of dynein arms and reduced sperm motility. Fibrous Sheath Dysplasia (FSD) is a flagellar pathology, which causes total sperm immotility, mainly due to hyperplasia and disorganization of the Fibrous Sheath (FS). Previous reports suggested that mutations in AKAP3 and AKAP4 genes (the main components of FS) might contribute to FSD. In a group of five Portuguese patients from Assisted Reproductive Medicine centres that presented totally sperm immotility, transmission electron microscopy revealed several structural defects in sperm flagellum, such as anomalies in dynein arms, microtubules  and  FS.  Given  the  importance of CCDC39, CCDC40, DNAH5, DNAI1, AKAP3 and AKAP4

genes in sperm motility, we decided to screen these genes in our patients. To identify genetic alterations that could explain their phenotype, we initiated the analysis of the exonic regions of these 6 genes by Sanger sequencing. We have already sequenced five genes and DNAH5 analysis is still ongoing (we have already sequenced thirty-five exons that are known to harbour a significant number of mutations, from a total of seventy-nine). Ten variants in CCDC39, twenty-six in CCDC40, two in DHAI1, seven in AKAP3, one in AKAP4 and thirty-nine in DNAH5 have been identified. The work’s major contribution was the identification of fourteen new variants in CCDC39, CCDC40, AKAP3 and DNAH5 genes. With this work we expect to be able to offer a differential diagnosis to the patients and find potential genetic markers for individuals with this kind of problem.