Whole-Exome Sequencing Identifies the VHL Mutation (c.262T > C, p.Try88Arg) in Non-Obstructive Azoospermia-Associated Cystic Renal Cell Carcinoma

Von Hippel-Lindau (VHL) genes are intimately involved in renal cell carcinoma (RCC), including clear cell RCC (ccRCC) pathogenesis. However, the contribution of pathogenic VHL mutations to ccRCC remains poorly understood. We report a xanthoderm with non-obstructive azoospermia (NOA)-associated cystic ccRCC, and the missense VHL mutation (c.262T > C, p.Try88Arg). In a 34-year-old patient, a urologic physical examination identified hard epididymis, and imaging tests revealed deferens-associated NOA, as well as multi-organ hydatid cysts, including bilateral epididymal cysts, bilateral testicular cysts, bilateral renal cysts, and pancreatic cysts. Five years later, ccRCC was developed based on clinical and radiologic evidence. Two different prediction models of protein structure and multiple sequence alignment across species were applied to assess the pathological effects of the VHL mutation. The reliability of the assessment in silico was determined by both the cellular location and protein levels of the mutant products, using IF and Western blot, respectively. Our study shows that the missense VHL mutation (c.262T > C, p.Try88Arg) plays a deleterious role in pVHL functions, as predicted by multiple sequence alignment across species. While a structural analysis identified no significant structural alterations in pVHL, the detrimental effects of this mutation were determined by exogenous expression, evidenced by a markedly different spatial distribution and reduced expression of mutant pVHL. This is the first report of the VHL gene mutation (c.475T > C, p.Try88Arg) in a xanthoderm.

Abnormal fertility, acrosome formation, IFT20 expression and localization in conditional Gmap210 knockout mice.

GMAP210 (TRIP11) is a cis-Golgi network-associated protein and a Golgi membrane receptor for IFT20, an intraflagellar transport component essential for male fertility and spermiogenesis in mice. To investigate the role of GMAP210 in male fertility and spermatogenesis, floxed Gmap210 mice were bred with Stra8-iCre mice so that the Gmap210 gene is disrupted in spermatocytes and spermatids in this study. The Gmap210flox/flox: Stra8-iCre mutant mice showed no gross abnormalities and survived to adulthood. In adult males, testis and body weights showed no difference between controls and mutant mice. Low-magnification histological examination of the testes revealed normal seminiferous tubule structure, but sperm counts and fertility were significantly reduced in mutant mice compared with controls. Higher resolution examination of the mutant seminiferous epithelium showed that nearly all sperm had more oblong, abnormally shaped heads, while the sperm tails appeared to have normal morphology. Electron microscopy also revealed abnormally shaped sperm heads but normal axoneme core structure; some sperm showed membrane defects in the midpiece. In mutant mice, expression levels of IFT20 and other selective acrosomal proteins were significantly reduced, and their localization was also affected. Peanut-lectin, an acrosome maker, was almost absent in the spermatids and epididymal sperm. Mitochondrion staining was highly concentrated in the heads of sperm, suggesting that the midpieces were coiling around or aggregating near the heads. Defects in acrosome biogenesis were further confirmed by electron microscopy. Collectively, our findings suggest that GMAP210 is essential for acrosome biogenesis, normal mitochondrial sheath formation, and male fertility, and it determines expression levels and acrosomal localization of IFT20 and other acrosomal proteins.