An effective preselection criterion for MODY with an increasingly positive genetic testing rate by NGS: results from two cohorts of Chinese children.

The purpose of this study was to determine the frequency of maturity-onset diabetes of the young (MODY) in two selected cohorts of Chinese children with diabetes and clinically suspected MODY, using next-generation sequencing (NGS). Ninety-three children who met the comprehensive criteria of suspected MODY were enrolled in two cohorts. A custom NGS panel or a whole exon group was used for sequencing. We identified 55/93 (59.1%) children with pathogenic and likely pathogenic MODY variants. Forty-two (76.3%) were confirmed to have the GCK (MODY2) mutation. Additionally, five had the HNF1A (MODY3), two the HNF1B (MODY5), one the 17q12 microdeletion (MODY5), two the HNF4A (MODY1), two the ABCC8 (MODY12), and one the PDX1 mutation (MODY4). Of these, 13 novel variants were detected in different genes. By comparing the gene-positive with gene-negative children, we found that discriminatory factors for MODY at diagnosis included lower HbA1c [7.4% vs. 10.2% (53 vs. 86 mmol/mol); P = 0.002], lower body mass index z score (0.2 vs. 1.0; P = 0.01), lower onset age (8.1 vs. 11.2 years; P = 0.001), and lower C-peptide (1.4 vs. 2.5 ng/mL; P = 0.02). In conclusion, the criteria used in this study for screening MODY are effective, and MODY2 is the most common subtype (76%), followed by MODY3 and MODY5. Some rare MODY subtypes have been reported in Chinese children.NEW & NOTEWORTHY We proved the clinical suspicion of maturity-onset diabetes of the young (MODY) according to the comprehensive criterion for next-generation sequencing testing, which helps to identify both common and rare MODYs, leading to accurate diagnosis and personalized treatment.

Polyethylene glycol recombinant human growth hormone in Chinese prepubertal slow-growing short children: doses reported in a multicenter real-world study.

BACKGROUND: To evaluate the effectiveness of individualized-dose polyethylene glycol recombinant human growth hormone (PEG-rhGH) for short stature. METHODS: This real-world study enrolled children with short stature in 19 hospitals throughout China. They were treated with PEG-rhGH for 6 months. The starting dosage ranged from 0.10 to 0.20 mg/kg/week. The primary outcome was the change in height standard deviation score (ΔHt SDS). RESULTS: Five hundred and ten patients were included and grouped based on dosage as A (0.10-0.14 mg/kg/week), B (0.15-0.16 mg/kg/week), C (0.17-0.19 mg/kg/week), and D (0.20 mg/kg/week). The mean 6-month ΔHt SDS for the total cohort was 0.49 ± 0.27, and the means differed among the four dose groups (P = 0.002). The ΔHt SDS was lower in group A than in groups B (LSM difference [95%CI], -0.09 [-0.17, -0.01]), C (LSM difference [95%CI], -0.10 [-0.18, -0.02]), and D (LSM difference [95%CI], -0.13 [-0.21, -0.05]) after adjusting baseline covariates. There were no significant differences among groups B, C, and D. When the baseline IGF-1 was < -2 SDS or > 0 SDS, the △Ht SDS was not different among the four groups (P = 0.931 and P = 0.400). In children with baseline IGF-1 SDS of -2 ~ 0 SDS, a higher dosage was associated with a better treatment effect (P = 0.003), and the △Ht SDS was lower in older children than in younger ones (P < 0.001). CONCLUSIONS: PEG-rhGH could effectively increase height in prepubertal short children. When the baseline IGF-1 was < -2 SDS, 0.10 mg/kg/week could be a starting dose. In other IGF-1 statuses, 0.15-0.20 mg/kg/week might be preferred. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03249480 , retrospectively registered.

Genetic and Phenotypic Spectrum of KBG Syndrome: A Report of 13 New Chinese Cases and a Review of the Literature.

KBG syndrome (KBGS) is a rare autosomal dominant inherited disease that involves multiple systems and is associated with variations in the ankyrin repeat domain 11 (ANKRD11) gene. We report the clinical and genetic data for 13 Chinese KBGS patients diagnosed by genetic testing and retrospectively analyse the genotypes and phenotypes of previously reported KBGS patients. The 13 patients in this study had heterozygous variations in the ANKRD11 gene, including seven frameshift variations, three nonsense variations, and three missense variations. They carried 11 variation sites, of which eight were previously unreported. The clinical phenotype analysis of these 13 patients and 240 previously reported patients showed that the occurrence rates of craniofacial anomalies, dental anomalies, global developmental delays, intellectual disability/learning difficulties, limb anomalies, and behavioural anomalies were >70%. The occurrence rates of short stature, delayed bone age, and spinal vertebral body anomalies were >50%. The frequency of global developmental delays and intellectual disability/learning difficulties in patients with truncated ANKRD11 gene variation was higher than that in patients with missense variation in the ANKRD11 gene (p < 0.05). Collectively, this study reported the genotypic and phenotypic characteristics of the largest sample of KBGS patients from China and discovered eight new ANKRD11 gene variations, which enriched the variation spectrum of the ANKRD11 gene. Variation in the ANKRD11 gene mainly caused craniofacial anomalies, growth and developmental anomalies, skeletal system anomalies, and nervous system anomalies. Truncated variation in the ANKRD11 gene is more likely to lead to global growth retardation and intellectual disability/learning difficulties than missense variation in ANKRD11.

The first familial NSD2 cases with a novel variant in a Chinese father and daughter with atypical WHS facial features and a 7.5-year follow-up of growth hormone therapy.

BACKGROUND: Wolf-Hirschhorn syndrome is a well-characterized genomic disorder caused by 4p16.3 deletions. Wolf-Hirschhorn syndrome patients exhibit characteristic facial dysmorphism, growth retardation, developmental delay, intellectual disability and seizure disorders. Recently, NSD2 gene located within the 165 kb Wolf-Hirschhorn syndrome critical region was identified as the key causal gene responsible for most if not all phenotypes of Wolf-Hirschhorn syndrome. So far, eight NSD2 loss of function variants have been reported in patients from different parts of the world, all were de novo variants. METHODS: In our study, we performed whole exome sequencing for two patients from one family. We also reviewed more NSD2 mutation cases in pervious literature. RESULTS: A novel loss of function NSD2 variant, c.1577dupG (p.Asn527Lysfs*14), was identified in a Chinese family in the proband and her father both affected with intellectual disability. After reviewing more NSD2 mutation cases in pervious literature, we found none of them had facial features that can be recognized as Wolf-Hirschhorn syndrome. In addition, we have given our proband growth hormone and followed up with this family for 7.5 years. CONCLUSIONS: Here we reported the first familial NSD2 variant and the long-term effect of growth hormone therapy for patients. Our results suggested NSD2 mutation might cause a distinct intellectual disability and short stature syndrome.

Efficacy and safety of octreotide treatment for diazoxide-unresponsive congenital hyperinsulinism in China.

IMPORTANCE: Octreotide is an off-label medicine for congenital hyperinsulinism (CHI), but is currently widely used for treatment of patients with CHI. Thus far, variable efficacy and adverse effects have been reported for octreotide. OBJECTIVE: The present study evaluated the efficacy and safety of a subcutaneous octreotide injection for treatment of diazoxide-unresponsive CHI in China. METHODS: This study was a retrospective review of children with diazoxide-unresponsive CHI who were treated with a subcutaneous octreotide injection. The efficacy and side effects of the treatment were assessed. RESULTS: Twenty-five Chinese children (15 boys) were involved in the study. Their median age at diagnosis was 8 weeks (range, 1-24 weeks) and median age at the final follow-up was 1.8 years (range, 0.3-3.3 years). Octreotide therapy effectively increased blood glucose levels in all patients. The intravenous glucose infusion rate was reduced in all patients. Twenty-one patients gradually discontinued the intravenous glucose infusion while receiving octreotide combined with frequent carbohydrate/glucose-rich feeding. Among patients with a monoallelic ATP-sensitive potassium (KATP) channel mutation, 50.0% showed gradual remission during follow up, indicating that the octreotide treatment may be a feasible alternative to surgery, especially for patients with monoallelic KATP-channel mutations. Transient elevation of liver enzymes occurred in 20.0% of patients, while asymptomatic gallbladder pathology occurred in one patient. The growth rates of these patients were normal (height standard deviation score was 0.3 ± 1.5 at the final follow-up). INTERPRETATION: Octreotide was a well-tolerated, effective therapy for most children with diazoxide-unresponsive CHI.

Clinical, biochemical, molecular and therapeutic characteristics of four new patients of mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency.

Thirty patients with mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS) deficiency, which is a rare autosomal recessive disorder caused by HMGCS2 gene mutation are known. Here, we present four new patients with this disease. The characteristics including several metabolites of patients were recorded. Next-generation targeted sequencing and multiple sequence alignment of PCR amplified products allowed for mutational analysis of HMGCS2. Minigene assay transcript analysis confirmed pathogenicity of a splice site mutation. All cases had recurrent episodes with infections while they had no symptoms during intermissions. Patient 1, a girl, showed recurrent severe metabolic acidosis after infections from 8 months old and presented with weakness, vomiting and lethargy but had normal blood glucose. After treatment, she revived completely. Patients 2, 3 and 4 were boys who showed episodes of hypoglycemia since 8, 27 and 10 months of age, respectively. Glucose infusion reversed the symptoms. All four patients had hepatomegaly and abdominal imaging showed fatty livers. Serum free fatty acid increased. Urinary dicarboxylic acids and urinary 4-hydroxy-6-methyl-2pyrone presented. Diagnosis was confirmed by HMGCS2 gene analysis and 7 mutations (p.R188H, p.F420S, p.R206C, IVS2 + 1G > T, p.E401*, p.A450Pfs*7 and p.Q427*) of this gene were found. Here we report on the characteristics and genetics of four new patients with HMGCS deficiency. This study will enrich our knowledge of this rare autosomal recessive disorder.

The diagnosis of cystinosis in patients reveals new CTNS gene mutations in the Chinese population.

Background Cystinosis is a rare autosomal-recessive disorder caused by a defective transport of cystine across the lysosomal membrane. Previous studies have mapped cystinosis to the CTNS gene which is located on chromosome 17p13, and various CTNS mutations have been identified to correlate them with this disease. Methods We analyzed six patients from five unrelated families who were diagnosed with cystinosis in our hospital. We described the diagnostic procedures for all the patients and proposed alternative therapies for cystinosis patients instead of using cysteamine, an orphan drug which was commercially unavailable in China. Moreover, genetic analysis of all patients' samples was carried out to identify novel CTNS gene mutations. Results and conclusions The patients in this study were followed up from 1 to more than 10 years to monitor their growth and development, which indicated that the alternative therapies we used were helpful to ameliorate the complications of the cystinosis patients without cysteamine. Furthermore, by sequencing the patients' genome, we identified novel mutations in the CTNS gene including: c.477C > G (p.S159R), c.274C > T (p.Q92X) and c.680A > T (p.E227V); these mutations were only observed in cystinosis patients and had never been reported in any other populations, suggesting they might be specific to Chinese cystinosis patients.

Increase in Peripheral Blood Intermediate Monocytes is Associated with the Development of Recent-Onset Type 1 Diabetes Mellitus in Children.

Monocytes play important roles in antigen presentation and cytokine production to achieve a proper immune response, and are therefore largely implicated in the development and progression of autoimmune diseases. The aim of this study was to analyze the change in the intermediate (CD14+CD16+) monocyte subset in children with recent-onset type 1 diabetes mellitus (T1DM) and its possible association with clinical parameters reflecting islet ß-cell dysfunction. Compared with age- and sex-matched healthy controls, intermediate monocytes were expanded in children with T1DM, which was positively associated with hemoglobin A1C and negatively associated with serum insulin and C-peptide. Interestingly, the intermediate monocytes in T1DM patients expressed higher levels of human leukocyte antigen-DR and CD86, suggesting better antigen presentation capability. Further analysis revealed that the frequency of CD45RO+CD4+ memory T cells was increased in the T1DM patients, and the memory T cell content was well correlated with the increase in intermediate monocytes. These results suggest that expanded intermediate monocytes are a predictive factor for the poor residual islet ß-cell function in children with recent-onset T1DM.

Genetic Analysis and Follow-Up of 25 Neonatal Diabetes Mellitus Patients in China.

AIMS: To study the clinical features, genetic etiology, and the correlation between phenotype and genotype of neonatal diabetes mellitus (NDM) in Chinese patients. METHODS: We reviewed the medical records of 25 NDM patients along with their follow-up details. Molecular genetic analysis was performed. We compared the HbA1c levels between PNDM group and infantile-onset T1DM patients. RESULTS: Of 25 NDM patients, 18 (72.0%) were PNDM and 7 (28.0%) were TNDM. Among 18 PNDM cases, 6 (33.3%) had known KATP channel mutations (KATP-PNDM). There were six non-KATP mutations, five novel mutations, including INS, EIF2AK3 (n = 2), GLIS3, and SLC19A2, one known EIF2AK3 mutation. There are two ABCC8 mutations in TNDM cases and one paternal UPD6q24. Five of the six KATP-PNDM patients were tried for glyburide transition, and 3 were successfully switched to glyburide. Mean HbA1c of PNDM was not significantly different from infantile onset T1DM (7.2% versus 7.4%, P = 0.41). CONCLUSION: PNDM accounted for 72% of NDM patients. About one-third of PNDM and TNDM patients had KATP mutations. The genetic etiology could be determined in 50% of PNDM and 43% of TNDM cases. PNDM patients achieved good glycemic control with insulin or glyburide therapy. The etiology of NDM suggests polygenic inheritance.

Knockdown of p66Shc by siRNA injection rescues arsenite-induced developmental retardation in mouse preimplantation embryos.

Two-cell arrest plays a principal role in the elevated levels of embryo loss during the first week of development in mouse. Previously, we have shown that arsenic can apparently induce 2-cell arrest in mouse preimplantation embryo and the expression of oxidative stress adaptor protein p66(Shc) is up-regulated in this process. In the present study, we demonstrated that microinjection of p66(Shc) siRNA into the pronucleus of zygotes resulted in a markedly decrease in both mRNA and protein levels of p66(Shc). The arsenite-induced 2-cell arrests, along with a reduction in the levels of reactive oxygen species (ROS), were significantly inhibited and the number of embryos developing to morula stage concurrently increased upon p66(shc) siRNA microinjection. These findings indicate that knockdown of p66(shc) improves the developmental competence of arsenite-exposed embryos in vitro by increasing the resistance to oxidative stress. In addition, we highlight the utility of single-embryo analysis in preimplantation embryos.

Arsenic impairs embryo development via down-regulating Dvr1 expression in zebrafish.

Exposure to environmental inorganic arsenic compounds has serious health effects on humans, including cancer, cardiovascular disease, developmental and reproductive problems. Our previous study showed that arsenic exposure caused various signs of toxicity in early stages of zebrafish development, including cardiac and neural system, such as pericardium edema, circulation failure, heart malformation. However, how arsenic exerts these effects is little known. Here, real-time quantitative RT-PCR and whole-mount in situ hybridization data showed that zebrafish Dvr1, a mammalian homolog of GDF1 related to the formation of left-right axis, was significantly down-regulated in embryos exposed to arsenite. Embryos with Dvr1 knockdown by antisense morpholino displayed abnormal development, including pericardium edema and failed looping, which is similar to the defects phenotype with arsenic treatment. Furthermore, overexpression of GDF1 significantly rescued development anomalies caused by morpholino or arsenite. Taken together, our results indicated for the first time that Dvr1 played an important role in the left-right asymmetry establishment of zebrafish embryo, and Dvr1 was involved in arsenic-mediated embryo toxicity, which gives novel insight into molecular mechanism of arsenic-mediated embryo toxicity.

Embryonic developmental toxicity of selenite in zebrafish (Danio rerio) and prevention with folic acid.

Selenium (Se) is an essential micronutrient, but also a potential toxin, which may be absorbed in excess. Relatively little is known about selenium embryotoxicity in zebrafish. In this study, we evaluated the effect of selenite exposure in zebrafish embryos. Selenite treatment decreased survival and resulted in abnormal development in a dose- and time-dependent manner. We observed irregular growth of neurons in selenite treated embryos, characterized by the absence of neurons in the brain, trunk and tail. Selenite exposure also induced defects in heart function, such as bradycardia and cardiac dysplasia with irregular and smaller chamber shape. In addition, selenite exposure caused ectopic cell proliferation, apoptosis, and a change in the pattern of DNA methylation. Our results suggested that supplementation with folic acid (FA) ameliorated the cardiac and neural defects in selenite-treated embryos. In conclusion, we demonstrated that selenite exposure caused cardiac and neural defects in zebrafish embryos and that folic acid protected against this embryotoxicity. It will give insight into the risk assessment and prevention of Se-mediated embryotoxicity.

A novel mutation impairing the tertiary structure and stability of γC-crystallin (CRYGC) leads to cataract formation in humans and zebrafish lens.

Congenital cataract is one of the leading causes of human blindness. In this study, we identified a novel, heterozygous c.385G

The identification of a novel mutation of nicotinic acetylcholine receptor gene CHRNB2 in a Chinese patient: Its possible implication in non-familial nocturnal frontal lobe epilepsy.

Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is partly caused by mutations in the nicotinic acetylcholine receptor (nAChR) genes CHRNA4, CHRNB2, and CHRNA2. Cases of non-familial nocturnal frontal lobe epilepsy (NFLE) are more common than the familial type and the phenotypes of the two are similar. CHRNA4 mutations have been found in sporadic NFLE, but no mutation in CHRNB2 or CHRNA2 have been reported. To analyze the genetic features of sporadic NFLE, we designed mutation screening of exon 5 of CHRNA4, exon 5 of CHRNB2, and exon 6 of CHRNA2, mutations in which are associated with ADFLE. We screened a group of 105 Chinese sporadic NFLE cases and identified a novel CHRNB2 mutation, V337G, in an evolutionary conserved region of the intracellular loop between transmembrane domains M3 and M4 in one patient. This mutation was not observed in the control group of 200 subjects. Bioinformatics analysis indicated that the mutation altered the hydrophobicity and secondary structure of the protein. To the best of our knowledge, this study established for the first time that CHRNB2 is potentially associated with non-familial NFLE patient. No mutations in CHRNA4 or CHRNA2 were revealed by our screening method.

A novel mutation in the connexin 50 gene (GJA8) associated with autosomal dominant congenital nuclear cataract in a Chinese family.

PURPOSE: To identify the genetic defect in a four-generation Chinese family with autosomal dominant congenital nuclear cataract. METHODS: Family history data were recorded. Clinical and ophthalmologic examinations were performed on family members. All the members were genotyped with microsatellite markers at loci associated with cataracts. Linkage analysis was performed after genotyping. Candidate genes were screened for mutation using direct sequencing. RESULTS: Linkage analysis was obtained at markers D1S1653 (LOD score [Z] = 1.50, recombination fraction [theta] = 0.0) and D1S498 (LOD score Z = 0.90, recombination fraction [theta] = 0.0), which encompasses the connexin 50 gene (GJA8). Sequencing the coding regions of GJA8 revealed a novel, heterozygous c.773C > T transition that resulted in the substitution of a highly conserved serine by phenylalanine at codon 258 (S258F). Bioinformatics analysis showed that the mutation altered the hydrophobicity and secondary structure of the protein. This mutation co-segregated with the disease phenotype in all affected individuals and was not found in the unaffected family members or in 100 normal unrelated individuals. CONCLUSIONS: This study has identified a novel missense mutation located in the carboxyl terminus of GJA8 (S258F) associated with autosomal dominant nuclear cataract.

[Gene mutation analysis of a collodion baby].

OBJECTIVE: To determine the mutations pattern of the genes of a collodion baby. METHODS: Collodion baby is a genetic heterogeneous disease caused by mutations of several genes. Since the most common mutations were observed in TGM1 gene, this gene was chosen for mutation screening. The screening was carried out by PCR and direct sequencing. The allele specific primers were designed for a missense mutation and allele-specific (AS) PCR was carried out in 50 normal individuals for population study. RESULTS: Three novel alterations were detected in TGM1 gene of the proband, a missense mutation c.463C > T (p.Arg155Trp) in exon 3, a nonsense mutation c.578G > A (p.Trp193X) in exon 4, and a single nucleotide deletion (c.694delG) also in exon 4 of TGM1 gene. This infant's father was heterozygote of c.694delG mutation, while his mother carried the two mutations (c.463C > T and c.578G > A) on the same chromosome. The missense mutation was not detected in his father and in any of the control individuals by AS-PCR. CONCLUSION: Three novel mutations were identified in TGM1 gene in a Chinese collodion baby. A double mutation (c.463C > T and c.578G > A) located on the maternal allele while the c.694delG deletion on the paternal allele.

A novel GPR143 duplication mutation in a Chinese family with X-linked congenital nystagmus.

PURPOSE: To elucidate the molecular genetic defect of X-linked congenital nystagmus in a Chinese family. METHODS: Genomic DNA was prepared from peripheral blood. We used allele-sharing analysis to identify the possible locus harboring the disease-causing gene. We screened for mutations in the G protein-coupled receptor 143 gene (GPR143) by direct sequencing of the polymerase chain reaction (PCR)-amplified exons. RESULTS: In analyzing the candidate gene, GPR143, in the linked region, a 19 base pair (bp) duplication mutation in exon 1 was detected after direct DNA sequence analysis, which cosegregated in all patients of this family and was present in obligate female carriers. CONCLUSIONS: The identified 19 bp duplication in GPR143 induces a frame-shift and a premature stop codon, resulting in a truncated protein of 105 residues. These results suggest that this novel mutation is associated with the congenital nystagmus observed in this Chinese family and further support that GPR143 mutations are the underlying pathogenesis of the molecular mechanism for congenital nystagmus.