Endocrine Abstracts

Objectives: Delayed puberty is thought to be common in boys with Duchenne muscular dystrophy [DMD]. To date, studies addressing its frequency are not available. This study aims to report the frequency of delayed puberty in DMD from clinical examination.

Methods: All boys with DMD aged at least 14 years in January 2022 known to the Glasgow paediatric neuromuscular service (2015-2022) were included. Thirty-seven boys were identified. All 37 boys had at least two clinical assessment of puberty by a paediatric endocrinologist between 12 to 18 years. Delayed puberty was defined based on testes volume and/or genital staging in comparison to puberty normogram [van Buuren et al 2013].

Results: Median latest age was 17.1 years (Range 14.0-22.9). Of the 37 boys, 25 (68%) had delayed puberty. Twenty-three boys were treated with testosterone for at least six months. Of the 25 with delayed puberty, 88% were on daily glucocorticoid between 12-14 years but only 50% of those with normal onset of puberty were on daily glucocorticoid (P<0.05). Only one boy (4%) with delayed puberty was not treated with glucocorticoid between 12-14 years; but 42% with normal onset of puberty were not treated with glucocorticoid. Delayed puberty was present in 79% of boys on daily glucocorticoid. In those with delayed puberty, 76% had a history of fragility fractures; but of those with normal onset of puberty, only 33% had fragility fractures (P<0.05). Two of 10 (20%) with delayed puberty who were treated with testosterone in adolescence remained hypogonadal as young adults. Early morning testosterone levels were <8nmol/l on two occasions and both recommenced adult replacement therapy.

Conclusion: Almost 80% of adolescents with DMD on daily glucocorticoid had evidence of delayed puberty. Our data calls for the consideration of testosterone therapy from an earlier age in boys on daily glucocorticoid than the generally accepted age of 14 years. Preliminary results suggest that a small percentage of men with DMD and delayed puberty remained hypogonadal as young adults despite achieving adequate adult secondary sexual characteristics with testosterone. Clarifying gonadal function at the time of transition is important, and clinical pathways should be developed.