Objective To describe the natural history of phenotype, growth and gonadal function in patients with partial androgen insensitivity syndrome.

Setting Tertiary paediatric endocrine centre.

Methods Retrospective evaluation of 14 male patients with partial androgen insensitivity syndrome (PAIS) with verified androgen receptor (AR) mutations. The authors recorded phenotypic characteristics at birth and external masculinisation score (EMS), registered longitudinal growth, circulating levels of testosterone, estradiol, luteinising hormone (LH), follicle-stimulating hormone (FSH), inhibin-B and sex hormone binding globulin (SHBG), in addition to phenotype at postpubertal follow up.

Results The EMS ranged from 5 to 12 in PAIS at birth. Six patients were born with hypospadias and all patients developed gynaecomastia in puberty. Eight of the patients received testosterone treatment. At follow-up penile size was impaired irrespective of EMS at birth, but responded to pubertal androgen therapy in some of the patients. Serum levels of testosterone, estradiol, SHBG and LH, but not FSH and inhibin B, were markedly elevated in puberty. Final height was 181.3 cm (165.7–190.5 cm) corresponding to an SD score of 0.7 (−2.1 to +2.1 SD, n=10).

Conclusion Gynaecomastia and impaired phallic growth are frequently observed in adults with PAIS, but may be ameliorated by androgen therapy. The authors suggest that male patients presenting with gynaecomastia in puberty, and elevated circulating levels of testosterone, estradiol and LH in puberty, but normal FSH, should be suspected of having PAIS and undergo genetic testing for AR mutations.