Isolated 'idiopathic' micropenis: hidden genetic defects?
F Paris1, K De Ferran, A Bhangoo
1Unité d'Endocrinologie Pédiatrique, Hôpital Arnaud de Villeneuve, CHU Montpellier, Montpellier Cedex 5, France.
International Journal of Andrology
|May 4, 2011
Summary
Isolated micropenis in boys may indicate underlying androgen pathway defects. Genetic testing for androgen receptor (AR) and steroidogenic factor 1 (SF1) gene mutations is crucial for diagnosis.
Area of Science:
- Pediatric Endocrinology
- Human Genetics
- Molecular Biology
Background:
- Micropenis is defined as a stretched penile length below 2-2.5 standard deviations for age.
- Potential causes include hormonal imbalances, genetic defects, and androgen pathway abnormalities.
- The etiology of isolated micropenis often remains unidentified.
Purpose of the Study:
- To investigate molecular defects in the androgen pathway in boys with isolated micropenis and normal testosterone levels.
- To identify genetic mutations associated with isolated micropenis.
Main Methods:
- Sequencing of androgen receptor (AR), 5α-reductase (5αR), and steroidogenic factor 1 (SF1) genes in 26 boys with isolated micropenis.
- Patients had 46,XY karyotype and normal hormonal profiles (LH, FSH, testosterone response to hCG).
Main Results:
- Mutations in the AR gene were identified in two patients.
- A novel mutation in the SF1 gene was found in one patient, who also had low inhibin B (InhB) levels.
- This study reports isolated micropenis as a presenting symptom of AR and SF1 mutations.
Conclusions:
- Isolated micropenis, even with normal testosterone, can signify androgen pathway molecular defects.
- Evaluating Anti-Mullerian hormone (AMH) and InhB is recommended for patients with isolated micropenis.
- Genetic mutation detection aids in diagnosis, treatment, and genetic counseling for affected individuals.
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