ESPE Abstracts

Introduction: Boys born small for gestational age (SGA) often have undermasculinized genitalia. Little is known about the pubertal development and gonadal function on a longer-term in this specific group of males.

Aims: To determine the (pubertal) development and long-term urological and endocrine outcome of undermasculinized boys born SGA compared to undervirilized boys born appropriate for gestational age (AGA).

Methods: Clinical data were retrieved from the I-DSD Registry on boys with non-specific 46, XY DSD who were aged ≥2 years at the time of the study. Statistical analyses included: Pearson Chi-Square, Fisher's Exact, unpaired Student t-test, Mann-Whitney U test and Shapiro-Wilk test, as appropriate.

Results: Data of 179 cases (115 SGA, 64 AGA) from twelve centers were included. At 2 years of age, 31/104 SGA boys (29.8%) had incomplete or absent catch-up growth. Sufficient catch-up growth was even less likely in cases with comorbidities, birth length or weight ≤-3SD or preterm birth (P=0.019, 0.017 and 0.030, respectively). Eight SGA cases had received growth hormone therapy. At last assessment, both SD-scores for height and weight were lower in SGA boys (both P<0.001) at a median age of 8.0 (SGA) and 7.7 years (AGA). Delayed neuromotor development was present in 19.6% and 1.9% of SGA and AGA boys, respectively (P=0.001). The number of reinterventions for hypospadias repair was similar in both groups (1 (2); P=0.836). At last assessment, nearly all cases had an external masculinization score of 12/12, with residual hypospadias being the most frequent cause of lower scores in both groups.

Postnatal or childhood treatment to stimulate penile growth was reported to have a good clinical effect in 38/42 (90.5%) SGA and 14/15 (93.3%) AGA cases. LH levels during minipuberty were higher in SGA boys, with lower peak testosterone levels post stimulation (P=0.037 and 0.040 respectively). The majority of cases had a spontaneous onset and uneventful course of puberty. At the end of puberty, no difference in sex hormone levels was observed between SGA and AGA boys.

Conclusions: About one-third of boys with non-specific XY DSD who have SGA show insufficient catch-up growth. The urological outcome and effect of treatments to increase penile size was similar between SGA and AGA cases. Our data suggest a dysfunction of infantile Leydig cells in SGA boys, which does not seem to persist in adult-type Leydig cells. Alternatively, alteration of the hypothalamic-pituitary-gonadal axis during infancy may underlie the hormonal changes found in SGA boys.