A patient with 47, XYY mosaic karyotype and congenital absence of bilateral vas deferens: a case report and literature review

BACKGROUND: The incidence of 47, XYY syndrome in live-born male infants is 1/1000. Due to its variable clinical symptoms, the diagnosis is easy to miss. The incidence of congenital bilateral absence of the vas deferens (CBAVD) in infertile men is 1–2%. The main cause is the mutation of CFTR and ADGAG2 genes. CASE PRESENTATION: The patient was a 33-year-old man who visited a doctor 5 years ago due to infertility. The investigation revealed that the patient’s secondary sexual characteristics, testicular, and penis development were normal, and there was no gynecomastia, but the bilateral vas deferens and epididymis were not palpable. Transrectal ultrasound showed that the left seminal vesicle was missing, and the right seminal vesicle was atrophied. No abnormality was observed in Y chromosome microdeletion. Karyotype analysis indicated that the patient was 46, XY/47, XYY mosaic. Genetic testing found heterozygous mutations at two sites of CFTR (c263T > G and c2249C > T). CONCLUSIONS: Herein, we report the rare case of a male patient with clinical manifestations of infertility, chromosome 46, XY/47, XXY mosaic type, simultaneously manifested as the absence of bilateral vas deferens. Two pathogenic heterozygous CFTR gene mutations were found. Given the low genetic risk of the disease, we recommend that patients undergo intracytoplasmic sperm injection (ICSI) for fertility assessment.