Ala 586 Asp mutation in androgen receptor disrupts transactivation function without affecting androgen binding

Area of Science:

• Genetics and Molecular Biology
• Endocrinology
• Developmental Biology

Background:

• Androgen insensitivity syndrome (AIS) is a disorder affecting sexual development in individuals with a 46,XY karyotype.
• Understanding the molecular mechanisms underlying AIS is crucial for diagnosis and management.

Observation:

• A familial case study investigated two sisters with a female phenotype despite a 46,XY chromosomal complement.
• Elevated testosterone (T) and luteinizing hormone (LH) levels were observed in affected individuals.

Findings:

• A C1760A substitution in the androgen receptor (AR) gene, resulting in an Ala 586 Asp amino acid change, was identified in affected family members.
• This mutation led to a near-complete loss of the transactivation function of the androgen-androgen receptor complex.
• Ligand binding to the androgen receptor was not significantly affected by the mutation.

Implications:

• The Ala 586 Asp mutation in the AR gene is pathogenic and directly contributes to the development of AIS.
• These findings enhance our understanding of androgen receptor function and its role in male sexual differentiation.
• In vitro functional assays are valuable tools for confirming the pathogenicity of identified AR gene mutations.