Nomogram aids management of boys with constitutional delay in growth and puberty

By Eleanor McDermid, Senior medwireNews Reporter

A puberty nomogram is better than the classical criteria for identifying boys with constitutional delay in growth and puberty (CDGP), report researchers.

Among 287 Danish boys with delayed puberty and no alternative diagnoses or associated comorbidities, 27% were classified as having CDGP using the classical criterion of genital stage 1 at age 14 years or older and 15% were classified with the criterion of having a testicular volume below 4 mL at the same age.

But the team’s nomogram allowed many more diagnoses; 60% received a CDGP diagnosis because their genital stage was more than 2 standard deviations (SD) below that expected for Danish boys at that age, and 51% did so because their testicular volume was more than 2 SD below that expected.

The 173 boys diagnosed with delayed genital stage using the nomogram also had “marked developmental delay” in pubic hair stage and testicular volume. Their luteinizing hormone, follicle stimulating hormone and inhibin B levels were subnormal or at the bottom of the normal range, as was their testosterone, which was undetectable in 23 of 125 boys with data.

“The advantage of the puberty nomogram is that it allows the clinician to evaluate whether pubertal progression is delayed at any time during pubertal development, and we believe that the nomogram allows meaningful separation of normal vs abnormal pubertal development, including both onset and progression”, say researcher Jacob Lawaetz (Copenhagen University Hospital, Denmark) and colleagues.

They believe it offers a “more rational” approach than simply identifying 14-year-old boys in genital stage 1.

In the whole cohort, 96 boys received oral testosterone undecanoate (TU), at an average starting dose of 40 mg/day for an average of 0.8 years. The dose was increased according to the characteristics of individual patients. One year of treatment was associated with a significant increase in height, from 1.9 to 1.5 SD below normal, and in predicted adult height, from 172.3 to 178.1 cm.

Treated boys entered and progressed through puberty; however, so did the boys who were not treated, although the researchers noted that a proportion of these completed puberty later than the treated boys.

“Importantly, no inappropriate bone age advancement was observed in subjects receiving oral TU independent of the obtained serum testosterone concentration”, the team writes in The Journal of Clinical Endocrinology & Metabolism. “Thus, no threshold appears to exist for circulating testosterone levels above which final height predictions are impaired.”

But the researchers “recognize that large randomized clinical trials are necessary for proper evidence-based recommendations.”

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