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.

Natural history and clinical features of hepatitis C virus infection during childhood: A nationwide, observational survey in Japan.

AIM: Few data on spontaneous clearance rates of cases of mother-to-child transmission of hepatitis C viral (HCV) infection are available in Japan. Furthermore, the treatment courses of interferon-based and direct-acting antiviral agent (DAA) therapies for children are also unclear. Our aim was thus to clarify the long-term natural progression of HCV infection and the treatment outcomes of children in Japan. METHODS: We conducted a combined multicenter, observational survey involving 65 pediatric institutions in Japan. Pediatric HCV infection cases with patients born between 1973 and 2021 were collected over the 11-year period from 2012 to 2022. A total of 563 patients were enrolled, with 190 excluded for having insufficient laboratory data or treatment information, resulting in 373 eligible cases. RESULTS: Of 328 cases of mother-to-child infection, 34 (10.4%) had spontaneous clearance, with a median time to spontaneous clearance of 3.1 years (range 0.9-7.2 years). Of the total 373 eligible cases, 190 received antiviral therapy (interferon-based therapy, 158; DAA therapy, 32). Sustained virologic response rates after first-line treatment were 75.3% (119/158) and 100% (32/32) for interferon-based therapy and DAA therapy, respectively, with the DAA group showing a shorter time from therapy initiation to viral negativity (2.7 vs. 1.0 months; p = 0.0031). CONCLUSIONS: Approximately 10% of Japanese children infected by mother-to-child transmission achieve spontaneous resolution of HCV infection. Our findings indicate that DAA therapy is safe and highly effective in Japanese children, achieving higher sustained virologic response rates and shorter time to clearance of the virus compared with interferon-based therapy.

Genotype-Phenotype Correlations in Thirty Japanese Patients with Congenital Hypothyroidism Attributable to TG Defects.

CONTEXT: Thyroglobulin (Tg), encoded by TG, is essential for thyroid hormone synthesis. TG defects result in congenital hypothyroidism (CH). Most reported patients were born before the introduction of newborn screening (NBS). OBJECTIVE: We aimed to clarify the phenotypic features of patients with TG defects diagnosed and treated since the neonatal period. SUBJECTS AND METHODS: We screened 1061 patients with CH for thirteen CH-related genes and identified thirty patients with TG defects. One patient was diagnosed due to hypothyroidism-related symptoms and the rest were diagnosed via NBS. Patients were divided into two groups according to their genotypes, and clinical characteristics were compared. We evaluated the functionality of the seven missense variants using HEK293 cells. RESULTS: Twenty-seven rare TG variants were detected, including fifteen nonsense, three frameshift, two splice-site, and seven missense variants. Patients were divided into two groups: thirteen patients with biallelic truncating variants and seventeen patients with monoallelic/biallelic missense variants. Patients with missense variants were more likely to develop thyroid enlargement with TSH stimulation than patients with biallelic truncating variants. Patients with biallelic truncating variants invariably required full hormone replacement, whereas patients with missense variants required variable doses of levothyroxine. Loss of function of the seven missense variants was confirmed in vitro. CONCLUSION: To our knowledge, this is the largest investigation on the clinical presentation of TG defects diagnosed in the neonatal period. Patients with missense variants showed relatively mild hypothyroidism with compensative goiter. Patients with only truncating variants showed minimal or no compensative goiter and required full hormone replacement.

First case report of dichorionic diamniotic twins with chronic enteropathy associated with the SLCO2A1 gene.

We report the case of twins diagnosed with chronic enteropathy associated with the SLCO2A1 gene (CEAS) based on characteristic ulcer findings, which required 8 years to diagnose. Both twins had similar symptoms, including anemia and growth failure but the gastrointestinal tract was not evaluated initially because of mild symptoms that were considered consistent with psychological etiology. The endoscopic findings of the firstborn child showed spiral ulcer scars and pseudodiverticulum formation without Helicobacter pylori infection or eosinophilic infiltration in the duodenum. Since the twins presented with ulcers of an unknown cause simultaneously and the first-born child had a spiral ulcer, CEAS was suspected. Genetic analysis and high levels of prostaglandin E major urinary metabolites in the urine led to a definitive diagnosis of CEAS.

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.

Reductions in estimated glomerular filtration rate during puberty in GH-treated children born small for gestational age are associated with prematurity and low birth weight, not the dosage of GH treatment.

GH treatment has been widely utilized for short-statured children born small for gestational age (SGA). Although SGA children are at a higher risk of renal dysfunction, the effect of GH treatment on renal function is still unclear. We have previously shown that GH treatment is not associated with renal dysfunction during the prepubertal period; however, its effect during the pubertal period has not been investigated. Accordingly, we herein retrospectively investigated creatinine-based estimated glomerular filtration rates (eGFR) in 26 short-statured children born SGA during puberty, defined as the period between the onset of puberty and cessation of GH treatment, and their association with parameters at birth and GH treatment. We found that eGFR did not decrease during the pubertal period; however, gestational week and birth weight were negatively and significantly correlated with percentage decrease in eGFR during the pubertal period. The percentage decrease in eGFR did not correlate with changes in the insulin-like growth factor-1 standard deviation score or average weekly GH dose. In conclusion, GH treatment was not associated with a reduction in eGFR in short-statured SGA children during puberty. Since low birth weight and prematurity were associated with reductions in eGFR during puberty, monitoring for renal function was mandatory regardless of GH treatment in short-statured children born SGA.

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.

Serum leucine-rich alpha-2 glycoprotein and calprotectin in children with inflammatory bowel disease: A multicenter study in Japan.

BACKGROUND AND AIM: Serum leucine-rich alpha-2 glycoprotein (LRG) and calprotectin have been studied as disease activity markers in adults with inflammatory bowel disease (IBD). We evaluated them in pediatric IBD patients. METHODS: Subjects under 17 years old undergoing care at 11 Japanese pediatric centers were retrospectively assigned to 3 groups representing Crohn's disease (CD), ulcerative colitis (UC), and normal controls (NC) with irritable bowel syndrome or no illness. Serum LRG and calprotectin were measured using commercial enzyme-linked immunosorbent assay kits. RESULTS: We enrolled 173 subjects, including 74 with CD, 77 with UC, and 22 NC. Serum LRG concentrations in active CD (median, 200 µg/mL) were significantly greater than in remission (81 µg/mL; P < 0.001) or NC (69 µg/mL; P < 0.001). Serum calprotectin concentrations in active CD (2941 ng/mL) also were significantly greater than in remission (962 ng/mL; P < 0.05) or NC (872 ng/mL; P < 0.05). Serum LRG concentrations in active UC (134 µg/mL) were significantly greater than in remission (65 µg/mL; P < 0.01) but not significantly greater than in NC (69 µg/mL); serum calprotectin concentrations in active UC (1058 ng/mL) were not significantly different from those in remission (671 ng/mL) or NC (872 ng/mL). In receiver operating characteristic analyses of LRG, calprotectin, C-reactive protein, and erythrocyte sedimentation rate for ability to distinguish active IBD from remission, CD and UC showed areas under receiver operating characteristic curves for LRG (0.77 and 0.70, respectively), exceeding those for calprotectin, C-reactive protein, or erythrocyte sedimentation rate. CONCLUSIONS: In pediatric IBD, serum LRG may better reflect disease activity than serum calprotectin, particularly in CD.

Very young children with Prader-Willi syndrome are refractory to growth hormone-associated decreases in free thyroxine levels.

The earlier initiation of growth hormone (GH) treatment for patients with Prader-Willi syndrome (PWS) who are younger than 2 years has become more prevalent. Because free thyroxine (FT4) levels are low during this period, GH may induce further reductions; however, limited information is currently available on this issue. Therefore, we herein performed age-dependent and time-course analyses of thyroid hormone levels in GH-treated PWS children. This retrospective analysis included genetically diagnosed PWS patients (N = 37, median age of 26 months). An age-dependent analysis was performed by subdividing subjects based on age [a younger group aged between 1 and 24 months (N = 16) and an older group between 25 and 84 months (N = 21)] and was followed by a multiple regression analysis with adjustments for sex and the cumulative GH dose per bodyweight. A time-course analysis of subjects who had not received levothyroxine during the first 18 months of GH treatment (N = 28) was conducted. A one-month treatment with GH decreased FT4 levels in the older group, but not in the younger group, and this was associated with increases in thyroid-stimulating hormone levels. A positive correlation was noted between age and decreases in FT4 levels independent of the cumulative GH dose per bodyweight. The time-course analysis revealed no changes in FT4 levels in the younger group, while transient decreases were observed in the older group. In conclusion, GH treatment causes age-dependent changes in FT4 levels. This result will help clinicians establish a therapeutic strategy to decide the necessity of levothyroxine supplementation in GH-treated children with PWS.

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.

Case of hypereosinophilic syndrome with gastrointestinal involvement showing tissue eosinophil cytolysis.

Hypereosinophilic syndrome (HES), which is characterized by eosinophilia in the peripheral blood, often causes various organ disorders, including those of the gastrointestinal (GI) tract. The eosinophils play a key role in inflammation in eosinophilic GI disorders (EGIDs), including HES with GI involvement. Here, we report a case of HES with GI involvement that showed major basic proteins (MBPs) deposition in the absence of marked eosinophilic infiltration in the mucosa of the GI tract. An 11-year-old boy presented with nausea and epigastric pain for one week. He had a history of idiopathic HES with eosinophilic cystitis, diagnosed at the age of 2 years. He had been taking a low dose of corticosteroids for 9 years. The peripheral blood eosinophil count was 2,254/µL. Endoscopy revealed a swelling of the duodenal bulb mucosa. Histological findings of the duodenal mucosa revealed chronic inflammation, but no evidence of significant eosinophil infiltration and we could not diagnose him with HES with GI involvement or EGID. Immunofluorescent staining for MBP and galectin-10 was performed to detect intact and cytolytic eosinophils (eosinophil extracellular trap cell death: EETosis). Marked MBP deposition was evident in a small number of intact eosinophils in tissues from the duodenum, gastric antrum, and terminal ileum. The current case illustrates the utility of immunostaining for the detection of persistent eosinophilic inflammation, especially when cytolytic eosinophils are dominant.

Histological analysis of testes in patients with 5 alpha-reductase deficiency type 2: Comparison with cryptorchid testes in patients without endocrinological abnormalities and a review of the literature.

As evidenced by the intact histology of the testes during infancy, testicular differentiation during the prenatal period occurs normally in individuals with 5 alpha-reductase type 2 deficiency (5αRD); however, a majority of these individuals suffer from azoospermia or oligospermia during adulthood, indicating that impaired spermatogenesis occurs postnatally. Although the accompanying cryptorchidism may be partly responsible for this process, the underlying mechanisms remain largely unknown. To address this issue, we retrospectively compared the histological findings of descended testes in a 3-mo-old patient and undescended testes in an 18-yr-old patient with 5αRD. In the latter, testicular histology was compared to that of cryptorchid testes obtained from five adolescent patients without endocrinological abnormalities. Histological findings of a 3-mo-old patient revealed normal number of germ cells with intact seminiferous tubules. In contrast, an 18-yr-old patient showed marked reduction in germ cell number and atrophic seminiferous tubules. The findings were very similar to those observed in cryptorchid testes without endocrinological abnormalities. These findings suggest that the decrease in germ cells in 5αRD patients may be at least partly caused by accompanying cryptorchidism. As the number of germ cells did not decrease during the infantile period, early orchiopexy is recommended to prevent a decrease in germ cell number and preserve fertility.

Subcutaneous adipose tissue is a positive predictor for bone mineral density in prepubertal children with Prader-Willi syndrome independent of lean mass.

OBJECTIVES: Emerging evidence suggests a fat depot-specific relationship with bone mineral density (BMD) in children, particularly in those who are overweight/obese. However, this has not yet been investigated in detail in children with Prader-Willi syndrome (PWS), a genetic syndrome characterized by a decreased lean mass (LM) and increased fat mass (FM). The objective of this study is to investigate the relationships of LM and FM, particularly fat distribution, with bone mineral parameters. METHODS: This is a retrospective and cross-sectional study. Forty-seven prepubertal Japanese children with PWS (22 males, mean age: 6.86 years) were included. No subjects had type 2 diabetes mellitus or osteoporotic medications. LM, FM, and BMD and bone mineral content in the total body less head and the lumbar spine were measured using dual-energy x-ray absorptiometry, in addition to subcutaneous/visceral adipose tissue (SAT/VAT), and the ratio of VAT to SAT (V/S) by computed tomography at the umbilical level. Bone mineral apparent density was calculated to correct for bone size. RESULTS: LM positively correlated with bone mineral parameters after controlling for age, sex, growth hormone (GH) treatment, and FM. Although FM did not correlate with bone mineral parameters, compartment-specific analysis revealed that SAT positively and V/S negatively correlated with bone mineral parameters after controlling for age, sex, GH treatment and LM. CONCLUSIONS: A compartment-specific effect of FM on bone mineral parameters was noted such that SAT was a positive predictor for BMD independent of LM in prepubertal children with PWS.

Clinical practice guidelines for the management of children with mother-to-child transmitted hepatitis C virus infection.

BACKGROUND: The first guidelines for care of pregnant women carrying the hepatitis C virus (HCV) and their infants were published in 2005 in Japan. Since then, evidence has gradually accumulated worldwide regarding the natural course and treatment of this condition and, especially in recent years, treatment for chronic hepatitis C in adult patients has made great progress. However, the clinical practice policy for children has not been standardized, and new clinical practice guidelines for children with mother-to-child (MTC) transmitted HCV infection have become necessary. METHODS: In the development of the current guideline, we requested cooperation from The Japanese Society for Pediatric Infectious Diseases, The Japan Society of Hepatology, and the Japan Society of Obstetrics and Gynecology. The committee members were recommended and approved by each society to participate in developing the guidelines. The guideline was also created in accordance with the Minds Guide for Practice Guideline Development. The statements were prepared by consensus-building using the Delphi method, based on the comprehensively searched academic papers and guidelines. These articles were retrieved through searching the PubMed, Cochrane Library, and the Igaku Chuo Zasshi databases. RESULTS: Eight clinical questions (CQs) with clinical statements were developed regarding etiology (CQs 1-3), diagnosis (CQs 4 and 5), and treatment (two CQs 6 and 7). In each statement, the consensus rate, evidence level, and recommendation level were determined. CONCLUSION: The guidelines will be helpful in the management of children with hepatitis C MTC transmission.

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.

Serum Zinc and Selenium in Children with Inflammatory Bowel Disease: A Multicenter Study in Japan.

BACKGROUND: Reports of zinc and selenium deficiencies accompanying inflammatory bowel disease (IBD) mostly have originated from Western countries and concerned adult patients. Whether Japanese children with IBD have similar deficiencies remained unclear. AIM: We aimed to elucidate differences in serum zinc and selenium concentrations in Japanese children between types of IBD. METHODS: Children under 17 years old undergoing care at 12 Japanese pediatric centers were retrospectively enrolled between November 2016 and February 2018 to 3 groups representing Crohn's disease (CD), ulcerative colitis (UC), and normal controls (NC) with irritable bowel syndrome or no illnesses. Serum zinc and selenium were measured by atomic absorption spectrophotometry. Zinc and selenium deficiencies were defined by serum concentrations < 70 µg/dL and < 9.5 µg/dL, respectively. RESULTS: Subjects included 98 patients with CD (median age, 13 years), 118 with UC (11 years), and 43 NC (11 years). Serum zinc and selenium were significantly lower in CD (median, 64 and 12.6 µg/dL respectively) than in UC (69 and 14.6; P < 0.05 and P < 0.001) or NC (77 and 15.7; P < 0.01 and P < 0.001). Zinc deficiency was significantly more prevalent in CD (60.2%) than in NC (37.2%; P < 0.05), but not than in UC (51.7%; P = 0.22). Selenium deficiency was significantly more prevalent in CD (15.3%) than in UC (5.9%; P < 0.05) or NC (0%; P < 0.01). CONCLUSIONS: In Japanese children under 17 years old, serum zinc and selenium were significantly lower in CD than in UC or NC. Zinc and selenium should be monitored, and supplemented when deficient, in children with IBD, especially CD.

Circulating insulin-like growth factor 1 levels are reduced in very young children with Prader-Willi syndrome independent of anthropometric parameters and nutritional status.

OBJECTIVE: Insulin growth factor-1 (IGF-1) is used to evaluate growth hormone (GH) sufficiency and is decreased in children with Prader-Willi syndrome (PWS). Although IGF-1 is negatively affected by body size and nutritional status, both of which are impaired in PWS children, these variables are typically not considered when assessing IGF-1 levels in these subjects. Here, we compared IGF-1 levels in PWS children to controls matched for age, sex, anthropometric parameters, and nutritional status. DESIGN/PATIENTS/MEASUREMENTS: The retrospective analysis included genetically diagnosed PWS subjects (n = 65, median age; 14.0 months) and controls (n = 111, 14.3 months) matched for age, sex, anthropometric parameters (height-standard deviation score [SDS], weight-SDS, body mass index-SDS), and serum albumin levels, a marker for nutritional status. IGF-1 SDS was compared between PWS subjects and controls after adjustment for confounding variables. The GH provocation test was performed in 29 PWS subjects, and IGF-1 SDS was compared between GH-sufficient (n = 20) and GH-deficient (n = 9) subjects. Spearman's rank correlation coefficient was performed to investigate the association between age and IGF-1 SDS. None had received GH or levothyroxine treatment. RESULTS: After adjustment for confounding variables, IGF-1 SDS was significantly lower in PWS subjects than controls (-1.56 vs. -1.01, p = .003), while it was not different between GH-sufficient and GH-deficient PWS subjects. Correlation analysis failed to show an association between age and IGF-1 SDS both in control and PWS groups. CONCLUSIONS: IGF-1 SDS is lower in very young children with PWS independent of anthropometric parameters and nutritional status, suggesting the presence of hypothalamic dysfunction of GH secretion.