Human Chorionic Gonadotropin Stimulation Test in Prepubertal Children with Micropenis Can Accurately Predict Leydig Cell Function in Pubertal or Postpubertal Adolescents.

BACKGROUND/AIM: To evaluate the accuracy of the human chorionic gonadotropin (hCG) stimulation test in children with micropenis in predicting later Leydig cell function. METHODS: We conducted a retrospective investigation of testosterone response to a 3-day hCG test (3,000 IU/m2/day) in prepuberty to indicate the need for hormone replacement therapy (HRT) in adolescence. RESULTS: Fifty Japanese boys (range, 0.8-15.4 years of age; median, 8.9) with micropenis were enrolled. Thirty-four spontaneously developed puberty and preserved the ability of testosterone production (group 1), while 16 did not develop any pubertal signs without HRT (group 2). Serum testosterone levels after the hCG test (post-hCG T) in group 2 (range, <0.05-1.1 ng/ml; median, 0.24) were significantly lower than in group 1 (range, 0.5-8.7 ng/ml; median, 2.4; p < 0.0001). Based on true positives who required continuous HRT, the area under the receiver-operating characteristics curve for post-hCG T was 0.983 [95% confidence interval (CI), 0.90-1.00]. The post-hCG T cut-off level corresponding to the Youden index was 1.1 ng/ml (95% CI, 1.0-1.1), with a sensitivity of 100.0% (95% CI, 79.4-100.0) and a specificity of 94.1% (95% CI, 80.3-99.3). CONCLUSIONS: The hCG test in prepubertal children with micropenis can be useful for predicting Leydig cell function in pubertal or postpubertal adolescents. The post-hCG T cut-off level of 1.1 ng/ml is recommended to screen for those who will likely require HRT for pubertal development.

MLL2 and KDM6A mutations in patients with Kabuki syndrome.

Kabuki syndrome is a congenital anomaly syndrome characterized by developmental delay, intellectual disability, specific facial features including long palpebral fissures and ectropion of the lateral third of the lower eyelids, prominent digit pads, and skeletal and visceral abnormalities. Mutations in MLL2 and KDM6A cause Kabuki syndrome. We screened 81 individuals with Kabuki syndrome for mutations in these genes by conventional methods (n = 58) and/or targeted resequencing (n = 45) or whole exome sequencing (n = 5). We identified a mutation in MLL2 or KDM6A in 50 (61.7%) and 5 (6.2%) cases, respectively. Thirty-five MLL2 mutations and two KDM6A mutations were novel. Non-protein truncating-type MLL2 mutations were mainly located around functional domains, while truncating-type mutations were scattered through the entire coding region. The facial features of patients in the MLL2 truncating-type mutation group were typical based on those of the 10 originally reported patients with Kabuki syndrome; those of the other groups were less typical. High arched eyebrows, short fifth finger, and hypotonia in infancy were more frequent in the MLL2 mutation group than in the KDM6A mutation group. Short stature and postnatal growth retardation were observed in all individuals with KDM6A mutations, but in only half of the group with MLL2 mutations.

SHOX nullizygosity and haploinsufficiency in a Japanese family: implication for the development of Turner skeletal features.

We report on clinical and molecular findings in a Japanese family consisting of a male infant with SHOX nullizygosity and his four family members with SHOX haploinsufficiency. The male infant had Langer mesomelic dysplasia, the prepubertal sister had idiopathic short stature phenotype with no discernible skeletal features, the father had mild Léri-Weill dyschondrosteosis (LWDC), and the mother and the maternal grandmother had moderate LWDC. The five subjects lacked clinically recognizable short metacarpals, cubitus valgus, high arched palate, short neck, and micrognathia, as well as recurrent otitis media and hearing loss. Fluorescence in situ hybridization and sequence analyses showed that the proband had a pseudoautosomal microdeletion involving SHOX and a C502T missense mutation in the homeobox domain at exon 4, and that the father was heterozygous for the SHOX deletion, and the sister, the mother, and the grandmother were heterozygous for the C502T mutation. The results, in conjunction with the previous findings, suggest that mesomelic skeletal features such as Langer mesomelic dysplasia and LWDC, which are absent or rare in Turner syndrome, are primarily caused by the SHOX dosage effect and the bone maturing effect of gonadal estrogens, whereas other skeletal features such as short metacarpals, cubitus valgus, and various craniofacial and cervical skeletal stigmata, which are common in Turner syndrome, are largely contributed by a compressive effect of distended lymphatics and lymphedema on the developing skeletal tissues.