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The mean height is taller in males than in females, except for early teens. In this regard, previous studies have revealed that (1) distribution of the mean adult heights in subjects with disorders accompanied by discordance between sex chromosome complement and bioactive sex steroids and in control subjects (the British height standards) indicates that, of the ~12.5 cm of sex difference in the mean adult height, ~9 cm is accounted for by the difference in the sex chromosome complement and the remaining ~3.5 cm is explained by the dimorphism in sex steroids (primarily due to the growth-promoting effect of gonadal androgens); (2) according to the infancy-childhood-puberty growth model, the sex difference in the childhood growth function produces height differences of ~1 cm in childhood and 8-10 cm at 18-20 years of age, whereas the sex difference in the pubertal growth function yields height difference of ~4.5 cm at 18-20 years of age; and (3) SHOX expression and methylation analyses using knee cartilage tissues and cultured chondrocytes have shown lower SHOX expression levels in female samples than in male samples and methylation patterns consistent with partial spreading of X-inactivation affecting SHOX in female samples. These findings suggest that small but persistent sex difference in SHOX expression dosage leads to the variation in the sex steroid independent childhood growth function, thereby yielding the sex difference in height which remains small in childhood but becomes obvious in adulthood.

Glutamic acid decarboxylase (GAD) is an enzyme that catalyzes the conversion of glutamic acid into γ-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the central nervous system (CNS). GAD is widely expressed in the CNS and pancreatic β-cells. GABA produced by GAD plays a role in regulating insulin secretion in pancreatic islets. Anti-GAD antibody is an established marker of type 1 diabetes mellitus (T1DM) and is also associated with stiff-person syndrome (SPS) and several other neurological disorders, including ataxia, cognitive impairment, limbic encephalitis, and epilepsy, collectively referred to as GAD antibody-spectrum disorders (GAD-SD). We report the case of a 17-year-old male patient who developed GAD-SD and T1DM after allogeneic hematopoietic cell transplantation (HCT). He presented with memory disorders, including feelings of déjà vu, accompanied by vomiting and headaches, and exhibited abnormal brain magnetic resonance imaging and electroencephalogram results. In addition to elevated fasting plasma glucose and glycated hemoglobin levels, markedly elevated anti-GAD antibody levels were detected in the serum and cerebrospinal fluid. Based on these findings, the patient was diagnosed with GAD-SD and T1DM and treated with methylprednisolone, followed by multiple daily insulin injections. We also reviewed previously reported cases of GAD-SD following HCT and multiple positive islet-related antibodies.

We report three Japanese patients with Sotos syndrome accompanied by marked overgrowth, i.e., a 2 8/12-year-old boy with a height of 105.2 cm (+4.4 SD) (patient 1), the mother of patient 1 with a height of 180.8 cm (+4.1 SD) (patient 2), and a 12 10/12-year-old girl with a height of 189.4 cm (+6.3 SD) (patient 3). In addition to the marked overgrowth (tall stature), patients 1-3 exhibited Sotos syndrome-compatible macrocephaly and characteristic features, whereas intellectual and developmental disabilities remained at a borderline level in patient 1 and were apparently absent from patients 2 and 3. Thus, whole exome sequencing was performed to confirm the diagnosis, revealing a likely pathogenic c.6356A>G:p.(Asp2119Gly) variant in NSD1 of patients 1 and 2, and a likely pathogenic c.6599dupT:p.(Ser2201Valfs*4) variant in NSD1 of patient 3 (NM_022455.5). The results, in conjunction with the previously reported data in nine patients with marked overgrowth (≥4.0 SD), imply that several patients with Sotos syndrome have extreme tall stature even in adulthood. Thus, it is recommended to examine NSD1 in patients with marked overgrowth as the salient feature.

SHORT syndrome is a rare developmental disorder frequently associated with growth failure and insulin resistant diabetes mellitus (IRDM). Since GH has a diabetogenic effect, GH therapy has been regarded as a contraindication. We observed a Brazilian girl with SHORT syndrome who received GH therapy from 4 6/12 years of age for SGA short stature. GH dosage was increased from 0.23 to 0.36 mg/kg/week, but statural response to GH therapy remained poor. Her blood HbA1c level, though it remained 5.5-6.0% in childhood, began to elevate with puberty and increased to 9.2% at 10 6/12 years of age, despite the discontinuation of GH therapy at 9 11/12 years of age. Laboratory studies indicated antibody-negative IRDM. She was treated with metformin and canagliflozin (a sodium glucose co-transporter 2 (SGLT2) inhibitor), which ameliorated overt diurnal hyperglycemia and mild nocturnal hypoglycemia and reduced her blood HbA1c around 7%. Whole exome sequencing revealed a de novo heterozygous pathogenic variant (c.1945C>T:p.(Arg649Trp)) in PIK3R1 known as the sole causative gene for SHORT syndrome. Subsequent literature review for patients with molecularly confirmed SHORT syndrome revealed the development of IRDM in 10 of 15 GH-untreated patients aged ≥12 years but in none of three GH-treated and six GH-untreated patients aged ≤10 years. These findings imply a critical role of pubertal development and/or advanced age rather than GH therapy in the development of IRDM, and a usefulness of SGLT2 inhibitor in the treatment of IRDM.

This 4-year randomized, double-blind, multicenter trial (NCT01927861) investigated the long-term efficacy and safety of Norditropin ® (NN-220; somatropin) in Japanese children with short stature due to Noonan syndrome. Pre-pubertal children with Noonan syndrome were randomized 1:1 to receive 0.033 mg/kg/day (n = 25, mean age 6.57 years) or 0.066 mg/kg/day (n = 26, mean age 6.06 years) GH. Height standard deviation score (SDS) change after 208 weeks from baseline was evaluated using an analysis of covariance model. Height SDS improved from -3.24 at baseline with a significantly greater increase (estimated mean [95% confidence interval]) with 0.066 vs. 0.033 mg/kg/day GH (1.84 [1.58; 2.10] vs. 0.85 [0.59; 1.12]; estimated mean difference 0.99 [0.62; 1.36]; p < 0.0001). The majority of treatment-emergent adverse events (TEAEs) were non-serious, mild and assessed as unlikely treatment-related. TEAE rates and frequencies of serious TEAEs were similar between groups. Three patients receiving 0.066 mg/kg/day were withdrawn; two due to TEAEs at days 1,041 and 1,289. Mean insulin-like growth factor-I SDS increased from -1.71 to -0.75 (0.033 mg/kg/day) and 0.57 (0.066 mg/kg/day) (statistically significant difference). In both groups, there were only minor glycosylated hemoglobin changes, similar oral glucose tolerance test insulin response increases and no clinically relevant changes in oral glucose tolerance test blood glucose, vital signs, electrocardiogram or transthoracic echocardiography. In conclusion, treatment with 0.033 and 0.066 mg/kg/day GH for 208 weeks improved height SDS in Japanese children with short stature due to Noonan syndrome with a significantly greater increase with 0.066 vs. 0.033 mg/kg/day GH and was well tolerated, with no new safety concerns.

This randomized double-blind multicenter trial (NCT01927861) evaluated the growth-promoting effect and safety of Norditropin ® (NN220; somatropin) in Japanese children with short stature due to Noonan syndrome. Prepubertal children aged 3-<11 years (boys) or 3-<10 years (girls) with Noonan syndrome were randomized to receive GH 0.033 mg/kg/day (n = 25, mean age 6.57 years, 11 females) or 0.066 mg/kg/day (n = 26, mean age 6.06 years, eight females) for 104 weeks. Change in height standard deviation score (HSDS) from baseline was analyzed based on an ANCOVA model. Baseline HSDS was -3.24. Estimated change in HSDS [95% CI] after 104 weeks' treatment was 0.84 [0.66, 1.02] and 1.47 [1.29, 1.64] for the lower and higher doses, respectively; estimated mean difference 0.63 [0.38, 0.88], p < 0.0001. Rates and patterns of adverse events (AEs) were similar between groups. Most were mild and reported as unlikely to be related to Norditropin ® . There were no withdrawals due to AEs. Insulin-like growth factor-I SDS increased from -1.71 to -0.64 (0.033 mg/kg/day) and to 0.63 (0.066 mg/kg/day). HbA 1c increased slightly (0.033 mg/kg/day: +0.14%; 0.066 mg/kg/day: +0.13%); glucose profiles were almost unchanged; insulin profiles increased in both groups in the oral glucose tolerance test. There were no clinically significant abnormal electrocardiogram or echocardiography findings. We conclude that Norditropin ® at doses of 0.033 mg/kg/day or 0.066 mg/kg/day for 104 weeks increases height in Japanese children with short stature due to Noonan syndrome, with a favorable safety profile. The effect was greater with 0.066 mg/kg/day compared with 0.033 mg/kg/day.

We report on a Japanese boy with Noonan syndrome who had short stature, bilateral cryptorchidism, poor pubertal development, mild mental retardation, complex cardiac lesions consisting of hypertrophic cardiomyopathy, mitral valve stenosis and insufficiency, subvalvular aortic stenosis, and single coronary artery, and various dysmorphic features including hypertelorism, epicanthic folds, low set malrotated ears, high arched palate, micrognathia, webbed neck, low posterior hairline, shield chest, pectus excavatum, cubitus valgus, borderline short metatarsals, lymphedema, redundant skin, and nail dysplasia. Because of marked lymphedema in the bilateral lower legs, lymphatic scintigraphy was carried out at 13.3 years of age, indicating extreme lymphstasis in the lower extremities, severe lymphstasis in the forearm, the elbow, and the axillary regions, moderate lymphstasis around the ascending aorta, and mild lymphstasis in the bilateral lungs. The results, in conjunction with those suggested in Turner syndrome, imply that lymphatic hypoplasia/dysplasia and resultant distended lymphatics and lymphedema are relevant to the development of not only soft tissue and visceral anomalies but also skeletal anomalies in Noonan syndrome.