Comparison of Oropharyngeal and Nasopharyngeal Swab Specimens for the Detection of Mycoplasma pneumoniae in Children with Lower Respiratory Tract Infection.

The oropharyngeal swab specimen was superior to the nasopharyngeal swab specimen for the detection of Mycoplasma pneumoniae in children with lower respiratory tract infection. The oropharyngeal loop-mediated isothermal amplification had 100% sensitivity and specificity compared with polymerase chain reaction testing, whereas the oropharyngeal rapid antigen detection test using immunochromatographic assay had relatively low sensitivity (66%) and reasonable specificity (90.7%).

Age-Adjusted Glycated Albumin at Diagnosis is more Correlated with the Product of Age and Plasma Glucose than Plasma Glucose Alone in Patients with Neonatal Diabetes Mellitus.

BACKGROUND: We previously showed that glycated albumin (GA) is a useful glycemic control indicator in patients with neonatal diabetes mellitus (NDM), and that age-adjusted GA (Aa-GA) can reflect more accurately glycemic control status. Here, we investigated whether the age at diagnosis influences Aa-GA at diagnosis of NDM. METHODS: Eight patients with NDM whose GA was measured at diagnosis (age at diagnosis: 39 ± 18 days; GA: 31.3 ± 7.6%; Aa-GA: 47.1 ± 10.3%; plasma glucose: 525 ± 194 mg/dl) were included. Aa-GA was calculated as follows: Aa-GA = GA × 14.0/[1.77 × log-age (days) + 6.65]. Correlations of GA or Aa-GA at diagnosis with its logarithmically transformed age in days (log-age), plasma glucose, and their product were investigated. RESULTS: GA at diagnosis was not significantly correlated with log-age or plasma glucose. On the other hand, Aa-GA at diagnosis was significantly positively correlated with plasma glucose (R = 0.75, P = 0.031) and was more strongly positively correlated with the product of plasma glucose and log-age (R = 0.82, P = 0.012) although it was not correlated with log-age. CONCLUSION: Aa-GA at diagnosis is influenced by both age in days and plasma glucose. This finding is likely to show the aspect that age in days is almost equal to diabetes duration because glycemic control indicators including GA reflect the weighted mean of plasma glucose.

A case of pancreatic agenesis and congenital heart defects with a novel GATA6 nonsense mutation: evidence of haploinsufficiency due to nonsense-mediated mRNA decay.

Recently, GATA6 heterozygous loss-of-function mutations were reported to cause pancreatic agenesis and congenital heart defects (PACHD [OMIM:600001]). However, the molecular mechanisms resulting from premature termination codons have not been examined in this disorder. The objective of this study was to perform a genetic analysis of a patient with PACHD. A female patient presented with ventricular septal defect, patent ductus arteriosus, and congenital diaphragmatic hernia at birth. Permanent neonatal diabetes mellitus and pancreatic exocrine deficiency due to pancreatic agenesis was diagnosed at 1 month of age. PCR-direct sequencing of GATA6 revealed that the patient is heterozygous for a novel de novo nonsense mutation of c.1477C>T, p. Arg493X in exon 5. RT-PCR direct sequencing of the RT-PCR products of total RNA from peripheral blood of the patient for the region encompassing exons 4-6 revealed only the wild-type allele. This finding provides the evidence for the occurrence of nonsense-mediated mRNA decay (NMD) in the p.Arg493X mutation. Quantitative RT-PCR analysis revealed that the expression of GATA6 transcript in the patient was less than half compared with normal control samples. This is the first evidence that GATA6 haploinsufficiency is caused by NMD in vivo, and we conclude that GATA6 haploinsufficiency causes not only PACHD but may affect other organs derived from the endoderm. Further screenings of GATA6 mutations in patients with various forms of diabetes and/or congenital heart disease with other visceral malformation may reveal the impact of GATA6 mutations on diabetes and congenital malformation.

Glycemic control and motor development in a patient with intermediate DEND.

The most common cause of neonatal diabetes, KCNJ11 gene mutation, can manifest as a neurological disorder. The most severe form consists of a constellation of developmental delay, epilepsy, and neonatal diabetes (DEND). Intermediate DEND (iDEND) refers to a milder presentation without epilepsy. We present a child with iDEND, for whom insulin injections were replaced with glibenclamide therapy at 17 months of age because of poor glycemic control and delayed motor development. Three months after initiation of glibenclamide, HbA1c decreased from 10.2% to 5.6%. Continuous glucose monitoring indicated that blood glucose fluctuations were suppressed while on glibenclamide. Furthermore, after initiating glibenclamide therapy, the developmental quotient (DQ) for motor ability markedly improved from 60 to 91, whereas the DQ for language and adoptive ability remained as they had been before the sulfonylurea treatment. Sulfonylurea treatment improved glycemic control and motor development in the present patient.

Evaluation of glycated hemoglobin and fetal hemoglobin-adjusted HbA1c measurements in infants.

BACKGROUND: As the presence of fetal hemoglobin (HbF) affects the accuracy of hemoglobin A1c (HbA1c) analysis methods, HbA1c measurement may not be a good indicator for patients with neonatal diabetes mellitus, whereas glycated albumin (GA) may be a good indicator. OBJECTIVE: To investigate whether total glycated hemoglobin (GHb) or HbF-adjusted HbA1c (adj-HbA1c) can act as a glycemic control marker in infants. SUBJECTS AND METHODS: Plasma glucose (PG), GA, HbF, GHb measured using the affinity method, and HbA1c measured using the latex-immunoturbidimetry (LA) or the high-performance liquid chromatography (HPLC) methods were determined in 26 full-term newborn infants aged 4-234 d. Adj-HbA1c was calculated as HbA1c/(total Hb - HbF). RESULTS: GHb, adj-HbA1c measured using the LA and the HPLC methods were 4.8 ± 0.5%, 4.5 ± 0.5%, and 4.7 ± 0.6%, respectively. GA was most positively correlated with PG (r = 0.696, p < 0.0001). GHb was positively correlated with both PG (r = 0.479, p = 0.013) and GA (r = 0.727, p < 0.0001). Adj-HbA1c measured using the LA method was positively correlated with GA (r = 0.465, p = 0.017), but not PG (r = 0.304, p = 0.132). Adj-HbA1c measured using the HPLC method was correlated with neither PG (r = -0.077, p = 0.710) nor GA (r = 0.360, p = 0.071). CONCLUSIONS: GHb measured using the affinity method may be a useful glycemic control marker in infants. Although adj-HbA1c measured using the LA method was correlated with GA, it may not be a practical measure because it was not correlated with PG and determining HbF levels using HPLC method can be troublesome. Adj-HbA1c measured using the HPLC method should not be used as a glycemic marker in infants.

Glycated albumin is lower in infants than in adults and correlated with both age and serum albumin.

BACKGROUND: Glycated albumin (GA) reflects glycemic control in patients with neonatal diabetes mellitus (NDM). However, GA in NDM patients is apparently low in relation to glycemia. OBJECTIVE: To establish the reference intervals for GA in healthy infants. SUBJECTS AND METHODS: Fifty-eight healthy, full-term newborn infants were used to define the GA reference values and to investigate its relationship to plasma glucose (PG) and serum albumin. The infants were categorized into three groups according to age: group A, 5 (4-6) median (range) d: n = 18; group B, 33 (30-38) d: n = 19; and group C, 181 (50-352) d: n = 21. We also studied 212 non-diabetic adults [group D, 53 (28-78) yr old] and the 5 NDM patients previously reported for GA comparisons. RESULTS: In the infants, GA was strongly positively correlated with logarithmic transformation of age [log (age)] (p = 0.831, p < 0.0001). The GA in groups A, B, C, and D were 7.3 ± 1.0%, 8.6 ± 1.1%, 10.9 ± 0.8%, and 14.0 ± 1.1%, respectively. The GA was more strongly positively correlated with serum albumin (r = 0.768, p < 0.0001) than with PG (r = 0.596, p < 0.0001). When GA levels were compared with the age-dependent reference values, GA in the transient NDM patient was normalized although GA in the four permanent NDM patients decreased but remained high after insulin therapy. CONCLUSIONS: This study showed that the reference range for GA in infants is lower than that of adults and increases with age, with which we confirmed that GA in the NDM patients reflected the clinical course. Consequently, GA in NDM patients should be compared with the age-based reference values to assess the accurate glycemic status.

A mutation of the ß-domain in POU1F1 causes pituitary deficiency due to dominant PIT-1ß expression.

BACKGROUND: POU1F1 encodes both PIT-1α, which plays pivotal roles in pituitary development and GH, PRL and TSHB expression, and the alternatively spliced isoform PIT-1ß, which contains an insertion of 26-amino acids (ß-domain) in the transactivation domain of PIT-1α due to the use of an alternative splice acceptor at the end of the first intron. PIT-1ß is expressed at much lower levels than PIT-1α and represses endogenous PIT-1α transcriptional activity. Although POU1F1 mutations lead to combined pituitary hormone deficiency (CPHD), no patients with ß-domain mutations have been reported. RESULTS: Here, we report that a three-generation family exhibited different degrees of CPHD, including growth hormone deficiency with intrafamilial variability of prolactin/TSH insufficiency and unexpected prolactinoma occurrence. The CPHD was due to a novel POU1F1 heterozygous variant (c.143-69T>G) in intron 1 of PIT-1α (RefSeq number NM_000306) or as c.152T>G (p.Ile51Ser) in exon 2 of PIT-1ß (NM_001122757). Gene splicing experiments showed that this mutation yielded the PIT-1ß transcript without other transcripts. The lymphocyte PIT-1ß mRNA expression was significantly higher in the patients with the heterozygous mutation than a control. A luciferase reporter assay revealed that the PIT-1ß-Ile51Ser mutant repressed PIT-1α and abolished transactivation capacity for the rat prolactin promoter in GH3 pituitary cells. CONCLUSIONS: We describe, for the first time, that the PIT-1ß mutation can cause CPHD through a novel genetic mechanism, such as PIT-1ß overexpression, and that POU1F1 mutation might be associated with a prolactinoma. Analysis of new patients and long-term follow-up are needed to clarify the characteristics of PIT-1ß mutations.

Unilateral adrenalectomy can be an alternative therapy for infantile onset Cushing' s syndrome caused by ACTH-independent macronodular adrenal hyperplasia with McCune-Albright syndrome.

We report herein the case of a 1-year-old boy with McCune-Albright syndrome (MAS) who presented with infantile-onset Cushing' s syndrome caused by ACTH independent macronodular adrenal hyperplasia (AIMAH). Abdominal CT, MRI, and adrenal scintigraphy with (131)I-adosterol identified bilateral adrenal involvement with the left adrenal gland being larger and functionally more active. Unilateral adrenalectomy of the left gland was performed and ameliorated many clinical symptoms, such as Cushingoid appearance and height restriction, and it also normalized many endocrinological data, such as diurnal rhythms of ACTH and cortisol, ACTH and cortisol responses to CRH, and urinary 24 hr free cortisol. Glucocorticoid was replaced for the first 1 year and 6 months after the operation. One adrenal crisis episode occurred at 3 weeks after the operation, but none have occurred since. These results suggest that unilateral adrenalectomy of the larger gland can be an alternative therapy for infantile onset Cushing' s syndrome caused by AIMAH with MAS, when asymmetric involvement is evident and the smaller gland is not markedly enlarged.

Increasing secular trends in height and obesity in children with type 1 diabetes: JSGIT cohort.

BACKGROUND: Recently, anthropometric indices in children with type 1 diabetes mellitus (T1DM) have begun to change. OBJECTIVE: To examine secular trends in patients' anthropometric indices. SUBJECTS: Japanese children with T1DM from the 1995, 2000, 2008 and 2013 cohorts of The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes. METHODS: We analysed serum haemoglobin A1c (HbA1c) levels, the incidence of severe hypoglycaemic events, the types and doses of insulin, height standard deviation scores (SDS), body mass index (BMI) percentiles compared with healthy Japanese children and obesity prevalence over time. We also stratified the patients according to glycaemic control levels of <58 mmol/mol (optimal), 58-75 mmol/mol (suboptimal) and ≥75 mmol/mol (high-risk). RESULTS: Data for 513-978 patients from each of the cohorts were analysed. The incidence of severe hypoglycaemic events decreased over time (from 21 to 4.8/100 patient-years), while the proportion of insulin analogue doses increased (14.6% to 98.6%). In addition, patient height SDS (-0.22 to +0.17), BMI percentile (52.1 to 58.7) and obesity prevalence (2.1% to 5.1%) increased. Height SDS increased in all of the glycaemic control subgroups, while BMI percentile and obesity prevalence increased in the suboptimal and high-risk groups. CONCLUSIONS: Since 1995, the average height of children with T1DM has increased in parallel with increasing insulin doses. Clinicians should be aware of increased BMI in these patients and the associated risk of developing cardiovascular disease in the future.

A 34-year-old Japanese patient exhibiting NBAS deficiency with a novel mutation and extended phenotypic variation.

Biallelic neuroblastoma amplified sequence (NBAS) gene mutations have recently been identified to cause a reduction in its protein expression and a broad phenotypic spectrum, from isolated short stature, optic nerve atrophy, and Pelger-Huët anomaly (SOPH) syndrome or infantile liver failure syndrome 2 to a combined, multi-systemic disease including skeletal dysplasia and immunological and neurological abnormalities. Herein, we report a 34-year-old patient with a range of phenotypes for NBAS deficiency due to compound heterozygous variants; one is a SOPH-specific variant, p.Arg1914His, and the other is a novel splice site variant, c.6433-2A>G. The patient experienced recurrent acute liver failure until early childhood. Hypogammaglobulinemia, a decrease in natural killer cells, and optic nerve atrophy were evident from infancy to childhood. In adulthood, the patient exhibited novel phenotypic features such as hepatic cirrhosis complicated by portal hypertension and autoimmune hemolytic anemia. The patient also suffered from childhood-onset insulin-requiring diabetes with progressive beta cell dysfunction. The patient had severe short stature and exhibited dysmorphic features compatible with SOPH, intellectual disability, and epilepsy. NBAS protein expression in the patient's fibroblasts was severely low. RNA expression analysis for the c.6433-2A>G variant showed that this variant activated two cryptic splice sites in intron 49 and exon 50, for which the predicted consequences at the protein level were an in-frame deletion/insertion, p.(Ile2199_Asn2202delins16), and a premature termination codon, p.(Ile2199Tyrfs*17), respectively. These findings indicate that NBAS deficiency is a multi-systemic progressive disease. The results of this study extend the spectrum of clinical and genetic findings related to NBAS deficiency.

Prevalence and risk factors of vitamin D deficiency rickets in Hokkaido, Japan.

BACKGROUND: Resurgence of vitamin D deficiency rickets has been recognized worldwide. While many cases of this disease have been reported in Hokkaido, the northern island of Japan, no prevalence data is available. Here, we investigated the prevalence and risk factors of vitamin D deficiency rickets in Hokkaido. METHODS: A specially designed questionnaire was sent to 84 major pediatric departments of hospitals in Hokkaido to collect information of the confirmed cases between July 1999 and June 2004. RESULTS: Sixty-seven hospitals responded to the questionnaire. Of these, 20 hospitals reported 31 confirmed cases. All the patients were infants and toddlers, less than 4 years of age. The prevalence of cases in a recent year was estimated to be nine in 100,000 children under four years of age. Most of the 31 cases in our study were breast-fed. Eleven cases showed signs of malnutrition due to unbalanced diet or dietary restriction. Furthermore, the prevalence of cases was higher in the northeastern region than in the southwestern region. The number of cases increased gradually from the end of winter to spring. CONCLUSIONS: This is the first report ascertaining the prevalence of vitamin D deficiency rickets in Hokkaido, Japan. Limited exposure to sunlight and inadequate diet in early childhood are key risk factors of this disease. Thus, it is crucial to introduce active recommendations for vitamin D supplementation based on age, residential area, and to advocate public awareness for preventing this disease.

Acute Pharyngitis Associated With Streptococcus dysgalactiae Subspecies equisimilis in Children.

BACKGROUND AND OBJECTIVES: The importance of Streptococcus dysgalactiae subsp. equisimilis (SDSE) in causing sporadic pharyngitis in children remains controversial. The aims of this study were (1) to report the incidence and (2) to compare the epidemiologic and clinical features of patients with SDSE to those with Streptococcus pyogenes (SP). METHODS: A prospective study was conducted on acute pharyngitis associated with SDSE in children over a 2-year period. SDSE was identified using a phenotypic method, M protein gene (emm) analysis and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Patients with positive SDSE or SP cultures received cephalosporins for 5 days and were followed up. The emm genotyping and specific virulence genes analyses were performed. RESULTS: From 3416 throat cultures, 67 isolates (2.0%) were identified as SDSE and 515 (15.1%) were identified as SP. The mean age of patients with SDSE (8.3 years) was older than those with SP (6.6 years; P < 0.01). There was minimal seasonal variation in the isolation rates of SDSE. The febrile patients' rates, gender distribution, cervical lymph node adenopathy rates, hospitalization rates, eradication and failure rates and the nonsuppurative sequelae between patients with SDSE and SP were similar. All SDSE isolates possessed important virulence genes. The emm genotyping of SDSE showed high strain diversity. CONCLUSIONS: The incidence of acute pharyngitis associated with accurately identified SDSE was 2/15 of that with SP. Epidemiologic and clinical features of acute pharyngitis associated with SDSE are indistinguishable from those with SP, with the exception of age and seasonal variation.

Four Japanese Patients with Congenital Nephrogenic Diabetes Insipidus due to the AVPR2 Mutations.

Almost 90% of nephrogenic diabetes insipidus (NDI) is caused by mutations in the arginine vasopressin receptor 2 gene (AVPR2) on the X chromosome. Herein, we reported clinical and biochemical parameters in four cases of three unrelated Japanese families and analyzed the status of the AVPR2. Two of the four patients had poor weight gain. However, in the male and female sibling cases, neither had poor weight gain while toddlers, but in the male sibling, episodes of recurrent fever, polyuria, and polydipsia led to the diagnosis of NDI at 4 years of age. Analysis of AVPR2 identified two nonsense mutations (c.299_300insA; p.K100KfsX91 and c.296G > A; p.W99X) and one missense mutation (c.316C > T; p.R106C). These mutations were previously reported. The patient with c.316C > T; p.R106C had milder symptoms consistent with previous reports. Of the familial cases, the sister was diagnosed as having NDI, but a skewed X-inactivation pattern in her peripheral blood lymphocytes was not identified. In conclusion, our study expands the spectrum of phenotypes and characterized mutations in AVPR2 in NDI.

Molecular basis of neonatal diabetes in Japanese patients.

CONTEXT: Neonatal diabetes mellitus (NDM) is classified clinically into a transient form (TNDM), in which insulin secretion recovers within several months, and a permanent form (PNDM), requiring lifelong medication. However, these conditions are genetically heterogeneous. OBJECTIVE: Our objective was to evaluate the contribution of the responsible gene and delineate their clinical characteristics. PATIENTS AND METHODS: The chromosome 6q24 abnormality and KCNJ11 and ABCC8 mutations were analyzed in 31 Japanese patients (16 with TNDM and 15 with PNDM). Moreover, FOXP3 and IPF1 mutations were analyzed in a patient with immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome and with pancreatic agenesis, respectively. RESULTS: A molecular basis for NDM was found in 23 patients: 6q24 in eleven, KCNJ11 in nine, ABCC8 in two, and FOXP3 in one. All the patients with the 6q24 abnormality and two patients with the KCNJ11 mutation proved to be TNDM. Five mutations were novel: two (p.A174G and p.R50G) [corrected] in KCNJ11, two (p.A90V and p.N1122D) in ABCC8, and one (p.P367L) in FOXP3. Comparing the 6q24 abnormality and KCNJ11 mutation, there were some significant clinical differences: the earlier onset of diabetes, the lower frequency of diabetic ketoacidosis at onset, and the higher proportion of the patients with macroglossia at initial presentation in the patients with 6q24 abnormality. In contrast, two patients with the KCNJ11 mutations manifested epilepsy and developmental delay. CONCLUSIONS: Both the 6q24 abnormality and KCNJ11 mutation are major causes of NDM in Japanese patients. Clinical differences between them could provide important insight into the decision of which gene to analyze in affected patients first.

[Excessive androgens and short stature in childhood].

Sex steroids play important role for bone maturation and statural growth in childhood, especially puberty. The closure of epiphyseal growth plate cartilage is regulated mainly by estrogens. Aromatization of androgens to estrogens is working in men as well as women. Thus, androgens are directly related to epiphyseal growth and maturation. In clinical conditions such as precocious puberty, excessive androgens production occurs in prepubertal period. This advances bone maturation as well as pubertal change resulting in short stature because of premature closure of epiphyseal growth plate. Various causes of precocious puberty are now identified.

High prevalence of DUOX2 mutations in Japanese patients with permanent congenital hypothyroidism or transient hypothyroidism.

BACKGROUND: Dual oxidase 2 (DUOX2) mutations are a cause of dyshormonogenesis (DH) and have been identified in patients with permanent congenital hypothyroidism (PH) and with transient hypothyroidism (TH). We aimed to elucidate the prevalence and phenotypical variations of DUOX2 mutations. METHODS: Forty-eight Japanese DH patients were enroled and analysed for sequence variants of DUOX2, DUOXA2, and TPO using polymerase chain reaction-amplified direct sequencing. RESULTS: Fourteen sequence variants of DUOX2, including 10 novel variants, were identified in 11 patients. DUOX2 variants were more prevalent (11/48, 22.9%) than TPO (3/48, 6.3%) (p=0.020). The prevalence of DUOX2 variants in TH was slightly, but not significantly, higher than in PH. Furthermore, one patient had digenic heterozygous sequence variants of both DUOX2 and TPO. CONCLUSIONS: Our results suggest that DUOX2 mutations might be the most common cause of both PH and TH, and that phenotypes of these mutations might be milder than those of other causes.

Age-adjusted glycated albumin accurately reflects blood glucose in patients with neonatal diabetes mellitus: comparison with calculated glycated albumin determined by past blood glucose concentrations.

BACKGROUND: Glycated albumin is a useful glycaemic control indicator for neonatal diabetes mellitus. However, glycated albumin concentrations in infants are lower than those in adults and increase in an age-dependent manner. Based on our investigation of non-diabetic subjects, we proposed the possibility that the reference range for adults may be used regardless of age, provided that age-adjusted glycated albumin is employed. In the present study, we evaluate the usefulness of age-adjusted glycated albumin in neonatal diabetes mellitus patients. METHODS: Six neonatal diabetes mellitus patients (four patients with permanent neonatal diabetes mellitus and two patients with transient neonatal diabetes mellitus) were included. Measured glycated albumin or age-adjusted glycated albumin was compared to calculated glycated albumin, which was determined using calculation formulae we had reported based on past blood glucose over the 50 days before measurement of glycated albumin. RESULTS: Measured glycated albumin was significantly lower than calculated glycated albumin (20.5 ± 4.9% versus 28.2 ± 6.1%; p < 0.0001), whereas age-adjusted glycated albumin was equivalent to calculated glycated albumin, showing no significant difference (27.5 ± 6.8% versus 28.2 ± 6.1%). Measured glycated albumin concentrations in patients with transient neonatal diabetes mellitus in remission were lower than the reference range for adults, whereas age-adjusted glycated albumin concentrations were within the reference range for adults. CONCLUSION: We demonstrated that age-adjusted glycated albumin concentrations were consistent with calculated glycated albumin. Age-adjusted glycated albumin is therefore a useful glycaemic control indicator for neonatal diabetes mellitus patients.

Age-adjusted glycated albumin: a more robust parameter to establish glycaemic control in neonatal diabetes mellitus.

BACKGROUND: We previously reported that glycated albumin (GA) levels increased in an age-dependent manner in infancy. In order to determine whether this phenomenon is true from infancy to adulthood, we investigated the GA levels in non-diabetic subjects of a wide range of age. METHODS: GA levels of 376 non-diabetic subjects [average age, 31.8 ± 23.8 years (4 days-78 years)] were determined. A relationship between GA and logarithmically transformed age [log(age)] was analysed. RESULTS: GA levels were significantly positively correlated with log(age) [R = 0.865, P < 0.0001, GA = 1.77 × log(day) + 6.55]. Based on a regression line, we established the formula for adjusting GA levels according to age. CONCLUSION: We showed that GA increases with age from infancy to adulthood and that normal GA levels are demonstrated as a simple regression formula with log(age). This formula allowing us to use the adult reference range has the potential for treatment monitoring of diabetic patients regardless of age.

HbA1c can be a useful glycemic control marker for patients with neonatal diabetes mellitus older than 20 weeks of age.

BACKGROUND: The accuracy of most HbA1c analysis methods is affected by the presence of increased fetal hemoglobin (HbF). The objective of this study was to investigate the age at which HbA1c measurements become useful for monitoring glycemic control in patients with neonatal diabetes mellitus (NDM). METHODS: We retrospectively analyzed the data of 5 NDM patients diagnosed at 38±20 days of age, who each had several available HbA1c measurements during the first year of life, with a control group of HbA1c values over the course of 1 year for 13 patients with type 1 diabetes mellitus (T1DM). Mean blood glucose (MBG) levels derived from premeal or premeal plus bedtime blood glucose measurements prior to HbA1c measurements were compared to HbA1c values. RESULTS: The NDM patients' age at which the difference in the HbA1c/MBG ratios became not significant between the NDM patients and the T1DM patients was 21 weeks of age and over. Even after the HbA1c was adjusted for HbF, this ratio was significantly lower in the NDM patients at <21 weeks of age than in the T1DM patients. CONCLUSIONS: HbA1c can be a useful glycemic control marker for NDM patients >20 weeks of age.

Quantitative and sensitive detection of GNAS mutations causing mccune-albright syndrome with next generation sequencing.

Somatic activating GNAS mutations cause McCune-Albright syndrome (MAS). Owing to low mutation abundance, mutant-specific enrichment procedures, such as the peptide nucleic acid (PNA) method, are required to detect mutations in peripheral blood. Next generation sequencing (NGS) can analyze millions of PCR amplicons independently, thus it is expected to detect low-abundance GNAS mutations quantitatively. In the present study, we aimed to develop an NGS-based method to detect low-abundance somatic GNAS mutations. PCR amplicons encompassing exons 8 and 9 of GNAS, in which most activating mutations occur, were sequenced on the MiSeq instrument. As expected, our NGS-based method could sequence the GNAS locus with very high read depth (approximately 100,000) and low error rate. A serial dilution study with use of cloned mutant and wildtype DNA samples showed a linear correlation between dilution and measured mutation abundance, indicating the reliability of quantification of the mutation. Using the serially diluted samples, the detection limits of three mutation detection methods (the PNA method, NGS, and combinatory use of PNA and NGS [PNA-NGS]) were determined. The lowest detectable mutation abundance was 1% for the PNA method, 0.03% for NGS and 0.01% for PNA-NGS. Finally, we analyzed 16 MAS patient-derived leukocytic DNA samples with the three methods, and compared the mutation detection rate of them. Mutation detection rate of the PNA method, NGS and PNA-NGS in 16 patient-derived peripheral blood samples were 56%, 63% and 75%, respectively. In conclusion, NGS can detect somatic activating GNAS mutations quantitatively and sensitively from peripheral blood samples. At present, the PNA-NGS method is likely the most sensitive method to detect low-abundance GNAS mutation.