Screening for mutations in candidate genes for hypospadias

Area of Science:

• Genetics
• Developmental Biology
• Endocrinology

Background:

• Hypospadias, a common male congenital malformation, involves abnormal urethral orifice placement.
• Normal male genital development relies on androgens (testosterone, dihydrotestosterone) and their receptor (androgen receptor).
• Mutations in genes like WT1, AR, and 5-alpha-reductase are potential causes of hypospadias.

Purpose of the Study:

• To investigate the role of mutations in the androgen receptor (AR), WT1, and 5-alpha-reductase genes in patients with hypospadias.
• To screen for point mutations in these candidate genes using polymerase chain reaction (PCR) and DNA sequencing.
• To determine the frequency of these gene mutations in isolated hypospadias and related conditions.

Main Methods:

• Exon-by-exon PCR amplification and DNA sequencing of AR, WT1, and 5-alpha-reductase genes.
• Analysis of 35 boys with hypospadias and one girl with complete androgen insensitivity syndrome.
• Screening for point mutations and splice mutations.

Main Results:

• No mutations in AR, WT1, or 5-alpha-reductase genes were identified in 26 patients with isolated hypospadias.
• Two patients with severe hypospadias and cryptorchidism had mutations in the androgen receptor (AR) gene.
• The girl with complete androgen insensitivity syndrome was homozygous for a splice mutation in the 5-alpha-reductase gene.

Conclusions:

• Mutations in WT1, AR, and 5-alpha-reductase genes are not frequent causes of isolated hypospadias.
• Androgen receptor (AR) gene mutations can be associated with severe hypospadias and cryptorchidism.
• 5-alpha-reductase gene mutations may play a role in conditions like complete androgen insensitivity syndrome.