Androgen receptor dysfunction as a prevalent manifestation in young male carriers of a FLNA gene mutation

Area of Science:

• Endocrinology
• Genetics
• Developmental Biology

Background:

• Androgen receptor (AR) signaling is crucial for male development, with cytoplasmic-to-nuclear translocation mediating gene transcription.
• Androgen insensitivity syndromes result from impaired AR function, affecting androgenic steroid actions.
• Filamin A (FLNA), a co-activator of AR, plays a role in its cytoplasmic localization and nuclear translocation.

Observation:

• Two brothers presented with gonadal differentiation disorder and hypospadias, linked to a loss-of-function mutation in the FLNA gene.
• Immunohistochemical analysis revealed a near-complete absence of AR in testicular tissue of affected individuals.
• This suggests a critical role for FLNA in AR localization and function within testicular cells.

Findings:

• Loss-of-function mutations in FLNA impair AR translocation and activation, causing male hypogonadism and gonadal developmental disorders.
• The observed phenotype in affected brothers mimics partial androgen insensitivity, underscoring the FLNA-AR pathway's importance.
• FLNA deficiency leads to significantly reduced AR presence in testicular tissue, impacting androgen signaling.

Implications:

• Investigating FLNA mutations is recommended for patients with cryptorchidism and epididymo-testicular dissociation, especially with suggestive family history.
• Monitoring growth and gonadal development in male patients with FLNA mutations from childhood is essential.
• Understanding the FLNA-AR interaction provides insights into male DSDs and potential therapeutic targets.