CFTR variants and renal abnormalities in males with congenital unilateral absence of the vas deferens (CUAVD): a systematic review and meta-analysis of observational studies

PURPOSE

CFTR variant is the main genetic contributor to congenital (unilateral/bilateral) absence of the vas deferens (CAVD/CUAVD/CBAVD). We performed a systematic review to elucidate the genetic link between CFTR variants, CUAVD, and the associated risk of renal abnormality (RA).

METHODS

We searched relevant databases for eligible articles reporting CFTR variants in CUAVD. The frequency of CFTR variants and RA, and the odds ratios (ORs) for common alleles and RA risk, were pooled under random-/fixed-effect models. Subgroup analyses and heterogeneity tests were performed.

RESULTS

Twenty-three studies were included. Among CUAVD patients, 46% had at least one CFTR variant, with 27% having one and 5% having two. The allele frequency in CUAVD was 4% for F508del and 9% for 5T. The summary OR for 5T risk in CUAVD was 5.79 compared with normal controls and 2.82 compared with non-CAVD infertile males. The overall incidence of RA was 22% in CUAVD. The pooled OR for RA risk among CUAVD patients was 4.85 compared with CBAVD patients.

CONCLUSION

CFTR variants are common in CUAVD, and the 5T allele may be associated with increased CUAVD risk. CUAVD patients bear a higher RA risk than CBAVD patients, but this is not associated with CFTR variants.

Abnormal cystatin C levels in two patients with bardet-biedl syndrome

Bardet-Biedl syndrome (BBS) is an autosomal recessive disorder characterized by central obesity, mental impairment, rod-cone dystrophy, polydactyly, hypogonadism in males, and renal abnormalities. The causative genes have been identified as BBS1-14. In the Western countries, the prevalence of this disease ranges from 1/13,500 to 1/160,000, while only a few Japanese patients have been reported in the English-language literature. The incidence of renal dysfunction or anomalies in previous reports varies considerably ranging from ∼20% to universal occurrence. We here report that two Japanese patients who had BBS with normal BUN and creatinine levels had elevated levels of cystatin C, a sensitive marker of glomerular filtration rate. A urine albumin level increased only in the elder patient. Thus, cystatin C may be useful for detecting renal abnormalities in patients with an apparent normal renal function. Because this disease is diagnosed by accumulation of symptoms, such a sensitive marker might help early diagnosis of BBS.

Unexpected Detection of Cephalad Renal Ectopia Due to Large Omphalocele Containing the Liver on Tc-99m DMSA Scintigraphy

Omphalocele is a congenital abdominal wall defect with herniation of abdominal viscera into a sac. Tc-99m DMSA renal cortical scan is a functional imaging technique used for detecting parenchymal defects, mostly in patients with recurrent urinary tract infection as well as congenital renal abnormalities. Renal anomalies are known to accompany omphalocele. In this retrospective study, we present a case of cephalad renal ectopia as observed on Tc-99m DMSA scintigraphy in a patient with omphalocele due to a large hernia sac containing most of the liver; and we review the renal abnormalities associated with omphalocele in the literature.