Mutations of CXorf6 are associated with a range of severities of hypospadias

Abstract

Objective: Mutations in chromosome X open reading frame 6 (CXorf6), a recently described candidate gene involved in the development of male genitalia, have been found in patients with complex 46,XYdisorders of sexual development (46,XY DSD) including micropenis, bifid scrotum, and penoscrotal hypospadias. The objective of this work was to identify genomic variants of CXorf6 in patients with isolated hypospadias, severe or non-severe. Design and methods: Forty-one patients with glandular to perineal hypospadias and thirty controls were studied. Direct sequencing for coding exons 3-6 of CXorf6 and their flanking splice sites was performed on DNA extracted from foreskin collected from surgery. Secondary and tertiary structures of the protein were predicted using NNpredict and Protein Homology/analogY Recognition Engine engines. Results: Four mutations (9.7% of cases) were identified. One missense mutation (1295TOC, V432A) and two deletions (325delG, predicted to cause a stop codon L121X) occurred in patients with penoscrotal and proximal hypospadias. One patient with subcoronal hypospadias had CAG-repeat amplification in the second polyglutamine domain of CXorf6. Secondary structure prediction indicated that this insertion occurred in a helix element of the protein. The tertiary structure prediction showed an alteration of the shape of the protein and crowding between domains. Conclusion: CXorf6 mutations are associated with isolated hypospadias of varying severity. However, the pathophysiology of these mutations and the function of the CXorf6 gene product remain to be investigated. European Journal of Endocrinology 159 453-458

Hypospadias in a Male (78,XY; <i>SRY</i>-Positive) Dog and Sex Reversal Female (78,XX; <i>SRY</i>-Negative) Dogs: Clinical, Histological and Genetic Studies

“…Further, it was noticed that divergent mutations of this gene are associated with a broad range of hypospadias phenotypes [Kalfa et al, 2008]. The c.325delG mutation resulting in a stop codon at the beginning of exon 3 was found in subjects with severe hypospadias.…”

‘Idiopathic’ partial androgen insensitivity syndrome in 28 newborn and infant males: impact of prenatal exposure to environmental endocrine disruptor chemicals?

“…Patients were diagnosed as cryptorchid if one or both testes were nonpalpable or if they could not be manipulated to a stable position at the bottom of the scrotum (19). Hypospadias was defined as a displacement of the urethral meatus from the tip of the glans penis to the ventral side of the phallus, scrotum, or perineum (20)(21)(22)(23)(24). In particular, hypospadias was graded as anterior (glandular and subcoronal locations), medium (distal penile and midshaft), or posterior (penoscrotal and perineal).…”

“…Direct sequencing of MAMLD1 coding exons and their flanking splice sites was performed with the 3130 Genetic Analyzer (Applied Biosystems, Foster City, CA, USA), using primers as described previously (21). Sequencing reactions were repeated twice with at least two different PCR products.…”

Long-term clinical course in three patients with <i>MAMLD1</i> mutations

“…years of age) [1][2][3][4][5], recent studies argue for MAMLD1/ Mamld1 being involved in the molecular network for T production: (i) MAMLD1/Mamld1 expression is upregulated by NR5A1 (alias, SF-1 and AD4BP) [6] that functions as the master regulator for multiple sex development and steroidogenic genes [7]; (ii) the wildtype mouse Mamld1 is clearly co-expressed with Nr5a1 in Leydig and Sertoli cells around the critical period for fetal sex development [1], and its intra-testicular expression level is gradually increased during the fetal life in parallel with the intra-testicular testosterone level [8]; (iii) transient Mamld1 knockdown using small interfering RNAs significantly reduces Cyp17a1 expression and T production in cultured mouse Leydig tumor cells [9]; and (iv) Mamld1 knockout male mice, though they are free from genital and reproductive abnormalities, show significantly lower expression levels of multiple fetal Leydig cell-specific genes includ-mutations were assessed as amorphic mutations.…”