Abstract
Background:
Exogenous androgen supplement is an optional treatment for micropenis; however, its use in childhood is controversial due to potential side effects.
Methods:
Twenty-three children (mean age: 4.07±3.4 years) with micropenis of unknown causes harboring the 46,XY karyotype were recruited in an open prospective study. Androgen receptor (AR), steroid 5α-reductase-2 (SRD5A2), and SRY genes were sequenced; 2.5% dihydrotestosterone (DHT) transdermal gel (0.1–0.3 mg/kg/day) was applied and titrated within the normal DHT serum reference ranges. Stretched penile length (SPL) was measured before therapy, and after 1, 3 and 6 months of DHT gel treatment, respectively.
Results:
Two patients were found with AR gene mutations and five patients with SRD5A2 gene mutations. Average stretched penile lengths (SPLs) were 1.68±0.6 cm at baseline and 2.2±0.66 cm, 2.6±0.59 cm and 2.9±0.55 cm (mean ± 1 SD) after 1, 3 and 6 months of treatment, respectively. Fourteen cases (61%) reached standard penile length ranges (>−2.5 SD) and medication was discontinued; six cases (26%) were satisfied with the improved penile lengths despite failing to reach the aged matched standards. Three infants (13%) discontinued the medication after 3 months due to anxiety about the potential side effects. No significant side effects were found except the elevated DHT serum levels after therapy.
Conclusions:
Short term and local application of DHT at low doses in patients with micropenis could accelerate penile growth effectively without evident side effects; however, precautions still need be taken due to the paucity of long term study and the lack of ideal DHT dosage.
Acknowledgments
The authors would like to thank all the children and their parents for their invaluable contributions for this study, and the authors are grateful to all the reviewers and editors for their efforts in making this manuscript suitable for publication.
Author contributions: Dan Xu contributed to blood sample collection, data analysis and interpretation, and manuscript drafting. Liangsheng Lu and Feihong Luo contributed to study conception and design, as well as critical revision for important content. The other authors contributed to data collection, analysis, and/or guidance, to different degrees. All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
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