A case of an infertile male with a small supernumerary marker chromosome negative for M-FISH and containing only heterochromatin.

AIM: To describe the case of a 32-year-old infertile male with small supernumerary marker chromosome (sSMCs) in 80% of peripheral lymphocytes.

METHODS

G-banding, C-banding, STRP analysis, M-FISH and molecule diagnosis of Y-chromosomal microdeletions were performed to determine the origin of sSMCs.

RESULTS

The karyotype of this patient was established as 47, XY, +mar/46, XY. C-banding showed that the marker chromosome was composed of heterochromatin without visible euchromatic material. No positive result was obtained in STRP, M-FISH and the microdeletion analysis of Y- chromosome.

CONCLUSIONS

The small supernumerary marker chromosome could play a causative role in male infertility although the mechanism remains to be elucidated.