Introduction

Pericentric inversions are seen on all chromosomes except chromosome number 20.¹ The most common pericentric inversion is chromosome 9 inversion with an incidence of 1.98%.² Pericentric inversion of the chromosome 9, inv (9) (p11q13), is such a common occurrence that some cytogeneticists would consider them as normal variants. Despite being categorized as a minor chromosomal rearrangement which does not correlate with abnormal phenotypes, many reports in the literature raised conflicting views regarding the association with subfertility and recurrent pregnancy loss, abnormal clinical conditions, as well as chromosomal abnormalities arising as a result of having this inversion.³

The ureteral bud arises from the distal mesonephric duct during the fifth week of pregnancy and extends in a dorsocranial fashion to meet the metanephric blastemia and induce differentiation to form the definitive kidney. With the differentiation of the mesonephric duct, the paradidymis, epididymis, vas deferens, ejaculatory duct, seminal vesicle, and hemitrigon are formed. For the development of a normal kidney both the ureteral bud and the mesonephric duct are required. The seminal vesicles develop as 12 distal mesonephric duct dilatations. The mesonephric duct then forms the vas deferens. Developmental defects of the mesonephric duct before the seventh week result in abnormalities of both the kidney and the reproductive tract, whereas if the defect occurs after the seventh week, the kidneys develop normally.⁴

A rare case is reported in which structural chromosomal aberration was accompanied by bilateral seminal vesicle agenesis and unilateral renal agenesis.

Case Presentation

A 27-year-old male patient was admitted to our clinic due to infertility. In the physical examination, the testicular volumes were normal (approximately 15 cc) and the bilateral vas deferens were palpable. Both semen analyses showed that the ejaculate volumes were low, azoospermic, and pellet negative. It has been reported that peripheral blood karyotype examination was 46 XY inv(9) (p11;q13) and no deletion was found in the AZF gene. Follicle-stimulating hormone (FSH) and total testosterone (TT) levels were detected as 11.31 mIU/ml and 5.55 ng/ml. It was reported that bilateral seminal vesicles were not observed in the transrectal ultrasonography examination. Pelvic MRI revealed that there was a 6 × 6 mm cyst located in the midline at the level of the prostate gland peripheral zone, and bilateral seminal vesicles were not observed (Figure 1). CT of the abdomen revealed agenesis of the left kidney (Figure 2). The gene analysis revealed no mutation was found in the ΔF508 gene which was performed for cystic fibrosis. Prenatal genetic counseling was recommended and microscopic testicular sperm extraction was performed. No viable sperm cells were found in the samples taken from the bilateral testicles. As a result of pathological evaluation, there was incomplete/complete atrophy in the 20% of seminiferous tubules. It was determined that only Sertoli cells were seen in 80% of them. In addition, significant thickening and hyalinization, focal Leydig cell hyperplasia were detected in the basement membranes of the seminiferous tubules and germ cells were not observed.

Discussion

The pericentric inversion of chromosome 9 [inv (9) (p11q13)] is recognized as a normal variant of chromosome 9. The inverted region contains only the centromere and centromeric heterochromatin, so it seldom results in aberrant chromosomes after crossing over.⁵ Colls et al (1997) investigated semen of a man with karyotype 46XY, inv (9) (p11q13). Inv (9) was found in 48.7% of analyzed cells and disomic sperm cells for chromosome 9 and 21 were not more frequent than in men with the normal karyotype. They concluded that inv (9) (p11q13) does not cause defects in spermatogenesis.⁶ Srebniak et al (2004) presented a subfertile man with 2 chromosomal inversions as 46 XY, inv (2) (p11q13), inv (9) (p11q13). In this case report, they recognized this abnormal karyotype was as a possible reason of spontaneous abortion.⁵ This inversion could cause some silent or mild problem in someone, which could cause severe problem in his/her children or grandchildren. So the evaluation of this chromosomal abnormality is important in infertile couples.

Seminal vesicle malformations are relatively rare and poorly known, causing male infertility in 2% of cases. They may be categorized into abnormalities of number (agenesis, fusion, duplication), maturation (hypoplasia), position (ectopia), or structure (diverticulum, cyst, communication with the ureter).⁸ In our patient, both the kidney and the reproductive tract abnormalities were found. In patients with congenital bilateral absence of the vas deferens, bilateral seminal vesicle agenesis was found in 23% to 43% of cases and unilateral seminal vesicle agenesis in 27% to 50% of cases. Also, patients with congenital unilateral absence of the vas deferens presented with ipsilateral seminal vesicle agenesis in 71% to 90% of cases and contralateral seminal vesicle agenesis in 20% of cases.⁹ However, although our patient had bilateral seminal vesicle agenesis, bilateral vas deferens were palpable. Bilateral or unilateral agenesis of the seminal vesicle or the vas deferens is often associated with a variable form of cystic fibrosis. There are no CFTR gene mutations in our patient. The clinical manifestations are caused by CFTR gene mutations.¹⁰ Therefore, it is reasonable to make a complete molecular analysis of the CFTR gene in cases of seminal vesicle or vas deferens birth defects.

In the literature review, no data could be found regarding the association and relationship between inv(9) and bilateral seminal vesicle agenesis in an infertile man. In conclusion, this is a rare case has a karyotype of 46 XY inv(9) (p11;q13) with bilateral seminal vesicle and unilateral renal agenesis without cystic fibrosis mutation.