Genetic backgrounds and genotype-phenotype relationships in anthropometric parameters of 116 Japanese individuals with Noonan syndrome.

Noonan syndrome (NS) is caused by pathogenic variants in genes encoding components of the RAS/MAPK pathway and presents with a number of symptoms, including characteristic facial features, congenital heart diseases, and short stature. Advances in genetic analyses have contributed to the identification of pathogenic genes in NS as well as genotype-phenotype relationships; however, updated evidence for the detection rate of pathogenic genes with the inclusion of newly identified genes is lacking in Japan. Accordingly, we examined the genetic background of 116 individuals clinically diagnosed with NS and the frequency of short stature. We also investigated genotype-phenotype relationships in the context of body mass index (BMI). Genetic testing revealed the responsible variants in 100 individuals (86%), where PTPN11 variants were the most prevalent (43%) and followed by SOS1 (12%) and RIT1 (9%). The frequency of short stature was the lowest in subjects possessing RIT1 variants. No genotype-phenotype relationships in BMI were observed among the genotypes. In conclusion, this study provides evidence for the detection rate of pathogenic genes and genotype-phenotype relationships in Japanese patients with NS, which will be of clinical importance for accelerating our understanding of the genetic backgrounds of Japanese patients with NS.

Utility of a rapid assay for prostaglandin E-major urinary metabolite as a biomarker in pediatric ulcerative colitis.

Prostaglandin E-major urinary metabolite (PGE-MUM) is a urinary biomarker reflecting ulcerative colitis (UC) activity. This prospective observational study aimed to evaluate the usefulness of PGE-MUM via rapid chemiluminescent enzyme immunoassay in detecting endoscopic remission (ER) and histologic remission (HR) in pediatric UC (6-16 years) in comparison with fecal calprotectin (FCP). ER and HR were defined as Mayo endoscopic score (MES) of 0 and Matts' histological grades (Matts) of 1 or 2, respectively. A total of 104 UC and 39 functional gastrointestinal disorder (FGID) were analyzed. PGE-MUM levels were significantly higher in the UC group than in the FGID group (P < 0.001). FCP levels were significantly elevated in the group without ER and HR than in the group with ER and HR (P < 0.001 and P = 0.001), whereas PGE-MUM levels were significantly higher in the group without ER compared to the group with ER (P < 0.001). No significant differences were noted in the AUCs for PGE-MUM and FCP in detecting ER and HR. Although PGE-MUM was inferior to FCP for the detection of HR, it might have the potential for application as a biomarker of endoscopic activity in pediatric UC owing to its noninvasive and rapid method.

A case of early-onset idiopathic chronic pancreatitis associated with a loss-of-function TRPV6 p.R483Q variant successfully treated by pancreatic duct stenting.

Several pancreatitis-related genetic variants have been identified. Recently, the association of loss-of-function variants in the transient receptor potential cation channel subfamily V member 6 (TRPV6) gene and early-onset non-alcoholic chronic pancreatitis (CP) has been reported. However, detailed clinical presentation of the cases carrying TRPV6 variants remains largely unknown. We report a case of early CP carrying a TRPV6 variant in which recurrent attacks of pancreatitis were successfully managed by pancreatic duct stenting. A 12-year-old boy with CP was referred to our hospital for further investigation. He had experienced recurrent pancreatitis attacks since he was 11 years old. Pancreatic ductal anomalies were not identified on magnetic resonance cholangiopancreatography. Genetic analysis revealed that the patient had a loss-of-function TRPV6 c.1448G > A (p.R483Q) variant in a heterozygous form. Conservative treatments were not effective; thus, we placed pancreatic duct stent by endoscopic intervention, and the frequency of relapses have dramatically decreased. We present the first pediatric report of early CP associated with the TRPV6 variant that was successfully treated with pancreatic duct stenting. This case suggests that pancreatic duct stenting is effective in preventing the relapse of pancreatitis related to the TRPV6 variant.

Dosage of hydrocortisone during late infancy is positively associated with changes in body mass index during early childhood in patients with 21-hydroxylase deficiency.

Obesity is a major complication in children with 21-hydroxylase deficiency (21-OHD). There is evidence to show that higher body mass index (BMI) during infancy and early childhood is associated with an increased risk for the subsequent development of obesity in the general population; however, limited information is currently available on this issue in 21-OHD patients. Additionally, despite the frequent use of supraphysiological dosages of hydrocortisone in 21-OHD, the association between BMI and hydrocortisone dosage during these periods remains largely unclear; therefore, we retrospectively investigated BMI at approximately 1 and 3 years old and its association with hydrocortisone dosage in 56 children with 21-OHD. The median BMI-standard deviation score (SDS) was 0.28 (Interquartile range [IQR]: -0.53 to 1.09) and 0.39 (IQR: -0.44 to 1.14) at approximately 1 and 3 years old, respectively, and no association was observed between hydrocortisone dosage and BMI-SDS at either time-point; however, multivariate analysis revealed that hydrocortisone dosage at approximately 1 year old was positively associated with changes in BMI (ß = 0.57, p = 0.013) and BMI-SDS (ß = 0.59, p = 0.011) between approximately 1 and 3 years old after adjustment for age, sex, and changes in hydrocortisone dosage during the same period. The average dosage of hydrocortisone between approximately 6 months and 1 year old also showed similar results. These results indicate that a higher dosage of hydrocortisone during late infancy is associated with a higher BMI at approximately 3 years old, which may lead to the development of obesity later in life in children with 21-OHD.

Beta-human chorionic gonadotropin-producing neuroblastoma: an unrecognized cause of gonadotropin-independent precocious puberty.

The pathogenesis of gonadotropin-independent precocious puberty (PP) includes both congenital and acquired forms, the latter of which may be associated with neoplasms, such as sex-steroid hormone-producing tumors. Beta-human chorionic gonadotropin (ß-hCG)-producing tumors also cause gonadotropin-independent PP by stimulating the production of testosterone in Leydig cells. Germ cell tumors and hepatoblastoma both produce ß-hCG; however, there is limited evidence to show that gonadotropin-independent PP is caused by other ß-hCG-producing tumors. We herein report the first case of ß-hCG-producing neuroblastoma associated with the development of gonadotropin-independent PP. A 2-year-old boy presented with an increased penile length, enlargement of the testes, pigmentation of the external genitalia, and growth acceleration. Imaging, blood, and urinary examinations revealed the presence of neuroblastoma in the right adrenal region. Decreased levels of luteinizing hormone and follicle-stimulating hormone with an increased testosterone level were indicative of gonadotropin-independent PP. Since serum ß-hCG was elevated, ß-hCG-producing neuroblastoma was suspected. Histological findings of the resected tumor were compatible with neuroblastoma. An immunohistochemical analysis using serial sections revealed staining for ß-hCG in synaptophysin-positive cells. Furthermore, immunofluorescence showed the co-staining of ß-hCG with neuron-specific enolase. These results suggested that ß-hCG was produced by tumor cells. Surgical removal of the tumor promptly normalized serum ß-hCG and testosterone levels. In conclusion, we propose the addition of neuroblastoma to the list of differential diagnoses of gonadotropin-independent PP with ß-hCG positivity in serum that includes germ cell tumors and hepatoblastoma.

Constitutional mismatch repair deficiency in childhood colorectal cancer harboring a de novo variant in the MSH6 gene: a case report.

BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) is caused by biallelic pathogenic variants in one of the mismatch repair genes, and results in early onset colorectal cancer, leukemia, brain tumors and other childhood malignancies. Here we report a case of CMMRD with compound heterozygous variants in the MSH6 gene, including a de novo variant in multiple colorectal cancers. CASE PRESENTATION: An 11-year-old girl, who presented with multiple spots resembling café-au-lait macules since birth, developed abdominal pain, diarrhea and bloody stool over two months. Colonoscopy revealed multiple colonic polyps, including a large epithelial tumor, and pathological examination revealed tubular adenocarcinoma. Brain magnetic resonance imaging (MRI) showed an unidentified bright object (UBO), commonly seen in neurofibromatosis type 1 (NF1). Genetic testing revealed compound heterozygous variants, c. [2969T > A (p.Leu990*)] and [3064G > T (p.Glu1022*)] in the MSH6 gene; c.2969T > A (p.Leu990*) was identified as a de novo variant. CONCLUSIONS: We present the first report of a CMMRD patient with a de novo variant in MSH6, who developed colorectal cancer in childhood. CMMRD symptoms often resemble NF1, as observed here. Physicians should become familiar with CMMRD clinical phenotypes for the screening and early detection of cancer.

Intussusception Caused by Percutaneous Endoscopic Gastrostomy With Jejunal Extension in Patients With Severe Motor and Intellectual Disabilities.

The risk of intussusception related to percutaneous endoscopic gastrostomy with jejunal extension (PEG-J) in patients with severe motor and intellectual disabilities (SMID) remains unknown. In a cross-sectional study, a review of 26 patients (mean age, 11.6 ± 6.4 years) with SMID who underwent PEG-J was performed. During the follow-up period, 6 of 26 (23%) patients developed intussusception. The median period from PEG-J to the onset of intussusception was 364 (range, 8-1344) days. No significant difference was observed in the Cobb angle between the intussusception and nonintussusception groups; however, body mass index at the time of PEG-J was significantly lower in the intussusception group. Intussusception related to PEG-J occurs relatively frequently in patients, and it is possibly attributable to factors such as deformity caused by undernutrition and weight loss. If enteral nutrition via PEG-J has been established, earlier enterostomy can be recommended because of the high risk of intussusception in patients with SMID.

Growth hormone treatment for extremely low birthweight children born small for gestational age.

BACKGROUND: The effectiveness of growth hormone (GH) treatment for height gain in short-stature children born small for gestational age (SGA) with extremely low birthweight (ELBW; birthweight <1,000 g) remains largely unknown. METHODS: In study 1, 35 prepubertal Japanese children born SGA with ELBW were categorized into three groups based on the presence or absence of catch-up growth by age 3 (CU(+) and CU(-), respectively) and GH treatment (GH(+) and GH(-), respectively). Height standard deviation (SD) scores (HT-SDS) in the CU-/GH+ group (n = 19) were compared with those in the age-matched CU+/GH- (n = 9) and CU-/GH- groups (n = 7). In study 2, 66 prepubertal Japanese SGA children treated with GH were divided into three groups by birthweight: <1,000 g (n = 19), 1,000-2,000 g (n = 20), and >2,000 g (n = 27). Changes in HT-SDS during the initial 3 years of GH treatment were compared among the three groups. RESULTS: In study 1, the mean HT-SDS in the CU-/GH+ group (-1.15 SD) was similar to that in the CU+/GH- group (-1.39 SD) but higher than that in the CU-/GH- group (-2.24 SD). In study 2, GH achieved a height gain of +1.62 SD in the ELBW group, which was similar to that in the other groups (1,000-2,000 g: +1.46 SD, >2,000 g: +1.53 SD). CONCLUSIONS: Growth hormone treatment in short-stature children born SGA with ELBW increased HT-SDS, which was similar to that in SGA children born with a birthweight ≥1,000 g. These results indicate that GH treatment may be an effective approach to promote adequate growth recovery for short-stature children born SGA with ELBW.

Fat distribution in short-stature children born small for gestational age.

BACKGROUND: Children born small for gestational age (SGA) with catch-up growth are at high risk for developing obesity; however, the characteristics of body composition, especially fat distribution, before and after growth hormone (GH) treatment in SGA children without catch-up growth remains largely unknown. METHODS: Anthropometric characteristics, body composition by dual-energy X-ray absorption, and fat distribution by computed tomography at the umbilical level were examined in 27 prepubertal short-stature children born SGA before and 1 year after GH treatment. RESULTS: Before GH treatment, short-stature SGA children had lean phenotypes, and both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were significantly lower than the age- and sex-matched Japanese reference values. Growth hormone treatment significantly increased height standard deviation scores (SDS), without affecting body mass index SDS. Percentage fat mass decreased with GH treatment; however, fat mass was not altered. Both VAT and SAT were significantly lower than the reference values after GH treatment. The ratio of VAT over SAT significantly increased by GH treatment. CONCLUSIONS: Both VAT and SAT were within or below the age- and sex-matched Japanese reference values in short-stature children born SGA before and after GH treatment, indicating that GH treatment may not have unfavorable effects on adiposity in short-stature children born SGA, although it may alter fat distribution.

Incidence of childhood primary immune thrombocytopenic purpura.

There is a discrepancy in the reported incidence of childhood immune thrombocytopenic purpura (ITP) between Europe (2.9-5.3 per 100 000 persons) and Japan (1.91). Ise district is a suitable area in which to conduct epidemiological study because there is little fluctuation in the sociodemographic factors. We performed a retrospective population-based study to clarify the incidence of primary childhood ITP. We calculated person-years for children aged <15 years based on the Ise district demographics between 2002 and 2012. The calculated person-years were 298 533. The number of hospitalized patients in Ise district was 25 (M/F, 14/11) during the study period. The calculated incidence was therefore 8.4 per 100 000 person-years. It is possible that the difference in incidence between the present calculation and that of the European studies is due to variation in accuracy and/or registration criteria between the studies.