Aim: Our aim was to describe the clinical and genetic findings in an adolescent male with isolated follicle-stimulating hormone (FSH) deficiency and demonstrate the efficacy of recombinant human FSH (rhFSH) replacement in this case.
Methods: A 14.5-year-old adolescent male was referred with normal pubertal development and small testes. Serum testosterone, FSH, and luteinising hormone (LH) were measured at baseline and after gonadotropin-releasing hormone (GnRH) stimulation. Testicular biopsy was performed, and rhFSH replacement was administered for 6 months. The patient's FSHβ gene was amplified and sequenced.
Results: Basal and GnRH-stimulated FSH levels were undetectable, in contrast with increased LH levels under both conditions. Histopathological investigation of a testicular biopsy specimen revealed a reduced number of Sertoli cells, the absence of germ cells, Leydig cell hyperplasia, and a thickened basement membrane in seminiferous tubules. The testicular size changed from 1 ml at baseline to 6 ml after 6 months of rhFSH replacement. Sequencing of the FSHβ gene exon 3 revealed a new missense mutation (c.364T>C, resulting in p.Cys122Arg) in a homozygous state in the patient; both parents and a sister carried the same mutation in a heterozygous state. We also compared our case with all similar cases published previously.
Conclusion: We herein described an adolescent male with isolated FSH deficiency due to a novel FSHβ gene mutation associated with a prepubertal testes size and normal virilisation.
© 2015 S. Karger AG, Basel.