[Cytogenetic and molecular study of a patient with severe oligozoospermia and asthenozoospermia]

To explore genetic etiologies of a patient with severe oligozoospermia and asthenozoospermia.

G-banded karyotyping and fluorescence in situ hybridization (FISH) were used to characterize the origin and structure of the abnormal chromosome discovered in this patient. Multiplex polymerase chain reaction (PCR) was used to detect microdeletion of azoospermia factor (AZF).

G-banding revealed a karyotype of 45,X,der(15) (?::p11.2→ qter)dn for the patient. Dual-color FISH confirmed that SRY gene was present in a segment attached to the short arm of chromosome 15. Sex chromosome mosaicism and numerical abnormality therefore were both present. Dual-color FISH revealed karyotype of nuc ish(DXZ1× 1, SRY× 1)[390/400]/(DXZ1× 2, SRY× 1) [10/400]. Four-color FISH showed that the abnormal chromosome 15 has derived from a pseudodicentric (Y;15) translocation, and that the breakpoint on Y chromosome was located at Yq12. G-banding and FISH results confirmed that the karyotype was 45,X,der(15)(?::p11.2→ qter)dn.ish psu dic(15;Y)(p11.2;q12)(D15Z1+ , SNRPN+ , PML+ ; SRY+ , DYZ3+ , DYZ1+ ). Microdeletion of AZFc combined with sY254 deletion was detected by multiplex PCR.

Cytogenetic and molecular genetic analysis of the patient has indicated meiotic disturbances with spermatogenetic arrest resulting from a pseudodicentric chromosome derived from Y;15 translocation and spermatogenesis dysfunction resulting from partial deletion of AZFc region.