Nighttime hypoglycemia in Japanese children with type 1 diabetes mellitus treated with multiple daily injection insulin therapy.

Prevention of hypoglycemia is an important strategy for glycemic management in patients with type 1 diabetes mellitus (T1D). Hypoglycemia is difficult to recognize at night while sleeping, particularly when using multiple daily injection (MDI) insulin therapy rather than sensor-augmented insulin-pump therapy. Therefore, it is possible that patients with T1D are at higher risk of nocturnal hypoglycemia when insulin is administered using an MDI regimen. We investigated nocturnal hypoglycemia in 50 pediatric patients with T1D on MDI insulin therapy using data from an intermittently scanned continuous glucose monitoring (isCGM) system. Hypoglycemia was observed on 446 of the 1,270 nights studied. Most of the hypoglycemic episodes were severe (blood glucose <54 mg/dL). On nights when hypoglycemia occurred, the blood glucose concentrations measured using finger-stick blood glucose monitoring (FSGM) before sleep and the next morning were lower than nights when hypoglycemia did not occur. However, few values were below the normal blood glucose range, suggesting that FSGM alone may be insufficient to detect nocturnal hypoglycemia. Approximately 7% of time was spent below the normal glucose range during the 10 hours from 21:00 to 7:00 the next morning. This result suggests that the patients on MDI insulin therapy could end up spending more time in hypoglycemia than is recommended by the American Diabetes Association (time below range <4.0% of time per day). Monitoring glucose levels overnight using an isCGM sensor may improve glycemic management via automatic detection of blood glucose peaks and troughs.

Germline-Derived Gain-of-Function Variants of Gsα-Coding GNAS Gene Identified in Nephrogenic Syndrome of Inappropriate Antidiuresis.

BACKGROUND: The stimulatory G-protein α-subunit encoded by GNAS exons 1-13 (GNAS-Gsα) mediates signal transduction of multiple G protein-coupled receptors, including arginine vasopressin receptor 2 (AVPR2). Various germline-derived loss-of-function GNAS-Gsα variants of maternal and paternal origin have been found in pseudohypoparathyroidism type Ia and pseudopseudohypoparathyroidism, respectively. Specific somatic gain-of-function GNAS-Gsα variants have been detected in McCune-Albright syndrome and may result in phosphate wasting. However, no germline-derived gain-of-function variant has been identified, implying that such a variant causes embryonic lethality. METHODS: We performed whole-exome sequencing in two families with dominantly inherited nephrogenic syndrome of inappropriate antidiuresis (NSIAD) as a salient phenotype after excluding a gain-of-function variant of AVPR2 and functional studies for identified variants. RESULTS: Whole-exome sequencing revealed two GNAS-Gsα candidate variants for NSIAD: GNAS-Gsα p.(F68_G70del) in one family and GNAS-Gsα p.(M255V) in one family. Both variants were absent from public and in-house databases. Of genes with rare variants, GNAS-Gsα alone was involved in AVPR2 signaling and shared by the families. Protein structural analyses revealed a gain-of-function-compatible conformational property for p.M255V-Gsα, although such assessment was not possible for p.F68_G70del-Gsα. Both variants had gain-of-function effects that were significantly milder than those of McCune-Albright syndrome-specific somatic Gsα variants. Model mice for p.F68_G70del-Gsα showed normal survivability and NSIAD-compatible phenotype, whereas those for p.M255V-Gsα exhibited severe failure to thrive. CONCLUSIONS: This study shows that germline-derived gain-of-function rare variants of GNAS-Gsα exist and cause NSIAD as a novel Gsα-mediated genetic disease. It is likely that AVPR2 signaling is most sensitive to GNAS-Gsα's gain-of-function effects.

Effects of pre- and post-pubertal dihydrotestosterone treatment on penile length in 5α-reductase type 2 deficiency.

Steroid 5α-reductase type 2 deficiency (5αRD2) is a congenital disorder of sex development caused by impairment of conversion from testosterone (T) to 5α-dihydrotestosterone (DHT). DHT deficiency leads to various degrees of undervirilized external genitalia including micropenis, primarily correlated with mutations of the SRD5A2 gene that encodes 5α-reductase type 2. Four Japanese boys with isolated micropenis were diagnosed as 5αRD2 by elevated ratios of serum T/DHT, and decreased ratios of urinary 5α/5ß-reduced steroid metabolites. Genetic analyses for SRD5A2 identified that the four patients shared a hypomorphic mutation R227Q that has a residual activity related to the mild-form of 5αRD2. For prepubertal micropenis, DHT was transdermally applied to the four patients at the ages of 4-11 year, increasing a median of stretched penile lengths (SPLs) from 2.6 cm (-2.5 SD) to 4.4 cm (-0.2 SD). Nevertheless, the post-pubertal penile growth was apparently retarded, despite normal levels of T secreted from well-developed testes. The second course of DHT treatment underwent at ages of 12-18 year, but unable to normalize SPLs at a range of 6.0 to 7.0 cm (-3.4 to -2.4 SD). The prostate volumes of two patients were variable at 8.1 and 21 cm3, and a sperm cell count of one patient was normal as young adult. DHT treatment contributes to development of the penis and prostate, which are favorable for the potential fertility of 5αRD2 adults. Meanwhile, the retarded penile growth and a risk of prostate overgrowth may complicate the post-pubertal management with DHT for 5αRD2 males.

MLL2 and KDM6A mutations in patients with Kabuki syndrome.

Kabuki syndrome is a congenital anomaly syndrome characterized by developmental delay, intellectual disability, specific facial features including long palpebral fissures and ectropion of the lateral third of the lower eyelids, prominent digit pads, and skeletal and visceral abnormalities. Mutations in MLL2 and KDM6A cause Kabuki syndrome. We screened 81 individuals with Kabuki syndrome for mutations in these genes by conventional methods (n = 58) and/or targeted resequencing (n = 45) or whole exome sequencing (n = 5). We identified a mutation in MLL2 or KDM6A in 50 (61.7%) and 5 (6.2%) cases, respectively. Thirty-five MLL2 mutations and two KDM6A mutations were novel. Non-protein truncating-type MLL2 mutations were mainly located around functional domains, while truncating-type mutations were scattered through the entire coding region. The facial features of patients in the MLL2 truncating-type mutation group were typical based on those of the 10 originally reported patients with Kabuki syndrome; those of the other groups were less typical. High arched eyebrows, short fifth finger, and hypotonia in infancy were more frequent in the MLL2 mutation group than in the KDM6A mutation group. Short stature and postnatal growth retardation were observed in all individuals with KDM6A mutations, but in only half of the group with MLL2 mutations.

Case of cytomegalovirus-associated direct anti-globulin test-negative autoimmune hemolytic anemia.

A 1-year-old boy developed autoimmune hemolytic anemia after a negative direct anti-globulin test. The concentration of erythrocyte membrane-associated immunoglobulin G, determined using an immunoradiometric assay, correlated with disease activity. He was positive for cytomegalovirus (CMV) both serologically and by quantitative real-time polymerase chain reaction, indicating that his autoimmune hemolytic anemia was directly caused by CMV infection. Since anti-CMV immunoglobulin G was not absorbed by the patient's erythrocytes, cross-reaction between erythrocyte antigens and CMV was not likely a causative factor for hemolysis.

Incidence and Risk Factors for Adrenal Crisis in Pediatric-onset Adrenal Insufficiency: A Prospective Study.

PURPOSE: To determine the incidence and risk factors for adrenal crisis (AC) in patients with pediatric-onset adrenal insufficiency (AI). MATERIALS AND METHODS: This multicenter, prospective cohort study conducted in Japan enrolled patients diagnosed with AI at ≤ 15 years of age. The incidence of AC was calculated as events per person-year (PY), and risk factors for AC were assessed using Poisson regression multivariable analysis. RESULTS: The study population comprised 349 patients (164 male, 185 female) with a total follow-up of 961 PY. The median age at enrollment was 14.3 years (interquartile range [IQR] 8.5-21.2 years), and the median follow-up was 2.8 years (IQR 2.2-3.3 years). Of these patients, 213 (61%) had primary AI and 136 (39%) had secondary AI. Forty-one AC events occurred in 31 patients during the study period. The calculated incidence of AC was 4.27 per 100 PY (95% confidence interval [CI] of 3.15-5.75). Poisson regression analysis identified younger age at enrollment (relative risk [RR] 0.93 [95% CI 0.89-0.97]) and increased number of infections (RR 1.17 [95% CI 1.07-1.27]) as significant risk factors. Female sex (RR 0.99 [95% CI 0.53-1.86]), primary AI (RR 0.65 [95 % CI 0.30-1.41]), or equivalent dosage of hydrocortisone per square meter of body area (RR 1.02 [95% CI 0.96-1.08]) was not a significant risk factor. CONCLUSION: A substantial proportion of patients with pediatric-onset AI experience AC. Younger age and an increased number of infections are independent risk factors for developing AC in these patients.

HLA-class II and class I genotypes among Japanese children with Type 1A diabetes and their families.

OBJECTIVE: To determine the HLA-DRB1, DQB1, DPB1, A, C, and B genotypes among Japanese children with autoimmune type 1 diabetes. METHODS: Four hundred and thirty patients who were GADAb and/or IA-2Ab-positive (Type 1A) were recruited from 37 medical centers as part of a nationwide multicenter collaborative study. DNA samples from 83 siblings of the children with Type 1A diabetes and 149 parent-child trios were also analyzed. A case-control study and a transmission disequilibrium test (TDT) were then performed. RESULTS: The susceptible and protective DRB1 and DQB1 alleles and haplotypes were confirmed. DPB1 alleles unique to the Japanese population and those common to multiple ethnic groups were also present. A linkage disequilibrium (LD) analysis showed both susceptible and protective haplotypes. The TDT did not reveal any alleles that were transmitted preferentially from the mother or father to children with Type 1A. Homozygosity for DRB1-09:01-DQB1-03:03 and heterozygosity for DRB1-04:05-DQB1-04:01 and DRB1-08:02-DQB1-03:02 were associated with an extremely high risk of Type 1A. A comparison of children with Type 1A and their parents and siblings suggested a dose effect of susceptible DRB1-DQB1 haplotypes and an effect of protective alleles on immunological pathogenesis. DRB1-09:01 appeared to be strongly associated with an early onset in preschool children with Type 1A diabetes. CONCLUSIONS: This study demonstrated the characteristic association of HLA-class II and class I genes with Type 1A diabetes among Japanese children. A TDT did not reveal the genomic imprinting of HLA-class II and class I genes in Type 1A diabetes.

Identification of chromosome 15q26 terminal deletion with telomere sequences and its bearing on genotype-phenotype analysis.

We report a de novo heterozygous 5,013,940 bp terminal deletion of chromosome 15q26 in a 13 9/12 -year-old Japanese girl with short stature (-3.9 SD), mild mental retardation, and ventricular septal defect (VSD). This terminal deletion involved IGF1R but not NR2F2, and was associated with an addition of telomere repeat sequences (TTAGGG) at the end of the truncated chromosome. The results provide further support for the notion that terminal deletions are healed by de novo addition of telomere sequences essential for chromosome stability and DNA replication. Furthermore, while growth failure and mental retardation are primarily explained by loss of IGF1R, the occurrence of VSD might suggest the existence of a cardiac anomaly gene, other than the candidate cardiac anomaly gene NR2F2, in the deleted region.

Complex role of the mitochondrial targeting signal in the function of steroidogenic acute regulatory protein revealed by bacterial artificial chromosome transgenesis in vivo.

The steroidogenic acute regulatory protein (StAR) stimulates the regulated production of steroid hormones in the adrenal cortex and gonads by facilitating the delivery of cholesterol to the inner mitochondrial membrane. To explore key aspects of StAR function within bona fide steroidogenic cells, we used a transgenic mouse model to explore the function of StAR proteins in vivo. We first validated this transgenic bacterial artificial chromosome reconstitution system by targeting enhanced green fluorescent protein to steroidogenic cells of the adrenal cortex and gonads. Thereafter, we targeted expression of either wild-type StAR (WT-StAR) or a mutated StAR protein lacking the mitochondrial targeting signal (N47-StAR). In the context of mice homozygous for a StAR knockout allele (StAR-/-), all StAR activity derived from the StAR transgenes, allowing us to examine the function of the proteins that they encode. The WT-StAR transgene consistently restored viability and steroidogenic function to StAR-/- mice. Although the N47-StAR protein was reportedly active in transfected COS cells and mitochondrial reconstitution experiments, the N47-StAR transgene rescued viability in only 40% of StAR-/- mice. Analysis of lipid deposits in the primary steroidogenic tissues revealed a hierarchy of StAR function provided by N47-StAR: florid lipid deposits were seen in the adrenal cortex and ovarian theca region, with milder deposits in the Leydig cells. Our results confirm the ability of StAR lacking its mitochondrial targeting signal to perform some essential functions in vivo but also demonstrate important functional defects that differ from in vitro studies obtained in nonsteroidogenic cells.

Status and trends in the use of insulin analogs, insulin delivery systems and their association with glycemic control: comparison of the two consecutive recent cohorts of Japanese children and adolescents with type 1 diabetes mellitus.

Background Treatment for type 1 diabetes mellitus (T1DM) has greatly changed by the general use of insulin analogs and continuous subcutaneous insulin infusion (CSII). To investigate whether these advances have been translated into continued improvement in glycemic control in Japanese children and adolescents, we analyzed the registration data of the two consecutive recent cohorts of Japanese childhood-onset T1DM patients. Methods The registration data including hemoglobin A1c (HbA1c), hypoglycemia and insulin regimen were compared between the two cohorts (862 patients in the 2008 cohort and 1090 in the 2013 cohort). Results The proportion of subjects with multiple daily insulin injection therapy (MDI) and CSII significantly increased (p<0.0001) from 67.4% and 9.7% to 71.8% and 23.4%, respectively. In the 2013 cohort, almost all patients were treated with basal-bolus treatment using insulin analogs. The use of CSII increased in all age groups, especially in the age group 0-5 years. The rates of overall, moderate and severe hypoglycemia significantly declined from 10.24, 10.18 and 0.056 events/100 persons/period in the 2008 cohort to 0.66, 0.62 and 0.033 in the 2013 cohort (p<0.0001, <0.0001, 0.04), respectively. Contrarily, there were no significant changes in HbA1c values between the two cohorts. Conclusions The popularization of the basal-bolus treatment using insulin analogs hascontributed to a significant decrease in hypoglycemia. In contrast, the intensive insulin treatment may not be enough for the satisfactory improvement of glycemic control in Japanese children and adolescents with T1DM. Considerable points remain, such as diabetic education and support to motivate patients.

Genetic defects in pediatric-onset adrenal insufficiency in Japan.

CONTEXT: Most patients with pediatric-onset primary adrenal insufficiency (PAI), such as 21-hydroxylase deficiency, can be diagnosed by measuring the urine or serum levels of steroid metabolites. However, the etiology is often difficult to determine in a subset of patients lacking characteristic biochemical findings. OBJECTIVE: To assess the frequency of genetic defects in Japanese children with biochemically uncharacterized PAI and characterize the phenotypes of mutation-carrying patients. METHODS: We enrolled 63 Japanese children (59 families) with biochemically uncharacterized PAI, and sequenced 12 PAI-associated genes. The pathogenicities of rare variants were assessed based on in silico analyses and structural modeling. We calculated the proportion of mutation-carrying patients according to demographic characteristics. RESULTS: We identified genetic defects in 50 (85%) families: STAR in 19, NR0B1 in 18, SAMD9 in seven, AAAS in two, NNT in two, MC2R in one and CDKN1C in one. NR0B1 defects were identified in 78% of the male patients that received both glucocorticoid and mineralocorticoid replacement therapy and had normal male external genitalia. STAR defects were identified in 67% of female and 9% of male patients. Seven of the 19 patients with STAR defects developed PAI at age two or older, out of whom, five did not have mineralocorticoid deficiency. CONCLUSIONS: Molecular testing elucidated the etiologies of most biochemically uncharacterized PAI patients. Genetic defects such as NR0B1 defects are presumed based on phenotypes, while others with broad phenotypic variability, such as STAR defects, are difficult to diagnose. Molecular testing is a rational approach to diagnosis in biochemically uncharacterized PAI patients.

Human Chorionic Gonadotropin Stimulation Test in Prepubertal Children with Micropenis Can Accurately Predict Leydig Cell Function in Pubertal or Postpubertal Adolescents.

BACKGROUND/AIM: To evaluate the accuracy of the human chorionic gonadotropin (hCG) stimulation test in children with micropenis in predicting later Leydig cell function. METHODS: We conducted a retrospective investigation of testosterone response to a 3-day hCG test (3,000 IU/m2/day) in prepuberty to indicate the need for hormone replacement therapy (HRT) in adolescence. RESULTS: Fifty Japanese boys (range, 0.8-15.4 years of age; median, 8.9) with micropenis were enrolled. Thirty-four spontaneously developed puberty and preserved the ability of testosterone production (group 1), while 16 did not develop any pubertal signs without HRT (group 2). Serum testosterone levels after the hCG test (post-hCG T) in group 2 (range, <0.05-1.1 ng/ml; median, 0.24) were significantly lower than in group 1 (range, 0.5-8.7 ng/ml; median, 2.4; p < 0.0001). Based on true positives who required continuous HRT, the area under the receiver-operating characteristics curve for post-hCG T was 0.983 [95% confidence interval (CI), 0.90-1.00]. The post-hCG T cut-off level corresponding to the Youden index was 1.1 ng/ml (95% CI, 1.0-1.1), with a sensitivity of 100.0% (95% CI, 79.4-100.0) and a specificity of 94.1% (95% CI, 80.3-99.3). CONCLUSIONS: The hCG test in prepubertal children with micropenis can be useful for predicting Leydig cell function in pubertal or postpubertal adolescents. The post-hCG T cut-off level of 1.1 ng/ml is recommended to screen for those who will likely require HRT for pubertal development.

SHOX nullizygosity and haploinsufficiency in a Japanese family: implication for the development of Turner skeletal features.

We report on clinical and molecular findings in a Japanese family consisting of a male infant with SHOX nullizygosity and his four family members with SHOX haploinsufficiency. The male infant had Langer mesomelic dysplasia, the prepubertal sister had idiopathic short stature phenotype with no discernible skeletal features, the father had mild Léri-Weill dyschondrosteosis (LWDC), and the mother and the maternal grandmother had moderate LWDC. The five subjects lacked clinically recognizable short metacarpals, cubitus valgus, high arched palate, short neck, and micrognathia, as well as recurrent otitis media and hearing loss. Fluorescence in situ hybridization and sequence analyses showed that the proband had a pseudoautosomal microdeletion involving SHOX and a C502T missense mutation in the homeobox domain at exon 4, and that the father was heterozygous for the SHOX deletion, and the sister, the mother, and the grandmother were heterozygous for the C502T mutation. The results, in conjunction with the previous findings, suggest that mesomelic skeletal features such as Langer mesomelic dysplasia and LWDC, which are absent or rare in Turner syndrome, are primarily caused by the SHOX dosage effect and the bone maturing effect of gonadal estrogens, whereas other skeletal features such as short metacarpals, cubitus valgus, and various craniofacial and cervical skeletal stigmata, which are common in Turner syndrome, are largely contributed by a compressive effect of distended lymphatics and lymphedema on the developing skeletal tissues.

Testicular dysgenesis without adrenal insufficiency in a 46,XY patient with a heterozygous inactive mutation of steroidogenic factor-1.

Steroidogenic factor-1 (SF-1) regulates multiple genes involved in the adrenal and gonadal development and in the biosynthesis of a variety of hormones, including adrenal and gonadal steroids, anti-Mullerian hormone (AMH), and gonadotropins. We identified a novel SF-1 mutation in a 27-yr-old Japanese patient with a 46,XY karyotype. Sequence analysis was performed for all the seven exons of SF-1, revealing a heterozygous single base pair deletion at exon 2 (18delC) that is predicted to cause a frameshift at the sixth codon and resultant termination at the 74th codon. Functional studies showed that the mutation produced no demonstrable protein and had no transcription activity or dominant negative effect. Clinical features included small dysgenetic testes with vasa deferentia and epididymides, absent uterus, blind-ending vagina, clitoromegaly, and psychosexual disturbance. Endocrine studies showed normal adrenal function (cortisol response to ACTH stimulation, 13.4-->25.3 microg/dl) and primary hypogonadism (testosterone response to hCG stimulation, 0.57-->0.76 ng/ml; gonadotropin responses to GnRH stimulation: LH, 10-->59 mIU/ml; FSH, 36-->69 mIU/ml), and urinary steroid hormone profile analysis indicated grossly normal steroidogenic enzyme activities. The results suggest that SF-1 haploinsufficiency can selectively impair testicular development and permit the biosynthesis of AMH and testosterone in dysgenetic testes and the production of gonadotropins in pituitary gonadotropes.

Micropenis and the 5alpha-reductase-2 (SRD5A2) gene: mutation and V89L polymorphism analysis in 81 Japanese patients.

The 5alpha-reductase-2 encoded by the SRD5A2 gene plays a critical role in male sex differentiation by converting testosterone into 5alpha dihydrotestosterone in the peripheral target tissues. In this study, we examined the SRD5A2 gene in 81 Japanese patients with micropenis (age, 0-14 yr; median, 7 yr) whose stretched penile lengths were between -2.5 SD and -2.0 SD in 39 patients (age, 0-13 yr; median, 8 yr) and below -2.5 SD in 42 patients (age, 0-14 yr; median, 6 yr), together with 100 control males (50 boys and 50 fertile adult males). Mutation analysis was performed for exons 1-5 and their flanking introns by denaturing HPLC and direct sequencing, revealing Y26X/R227Q in an 11-yr-old boy with a penile length of -2.6 SD, G34R/R227Q in a 9-yr-old boy with a penile length of -3.6 SD, and R227Q/R227Q in a 3-yr-old boy with a penile length of -2.4 SD, together with heterozygous R227Q in a control boy and a fertile adult male. Polymorphism analysis was carried out for the most frequent V89L known to reduce the enzyme activity by approximately 30% in 78 patients, except for the three patients with SRD5A2 mutations, and in the 100 control males by direct sequencing, showing that allele and genotype frequencies were similar between 78 patients with micropenis below -2.0 SD or 40 patients with micropenis below -2.5 SD and the 100 control males, the 50 boys, or the 50 fertile adult males, with no statistically significant differences. The results suggest that, in Japanese patients, micropenis can be caused by SRD5A2 gene mutations, especially by R227Q which has been shown to retain approximately 3.2% of normal enzyme activity and appears relatively frequent in Asian populations, and that V89L polymorphism is unlikely to raise the susceptibility to the development of micropenis.

Novel mutation of TBX3 in a Japanese family with ulnar-mammary syndrome: implication for impaired sex development.

We report on a Japanese family (two brothers and their mother) with ulnar-mammary syndrome (UMS). Clinical features included hypoplasia or aplasia of upper limbs on the ulnar side in the three affected individuals, micropenis with or without cryptorchidism, and hypoplastic nipples in the brothers; and hypoplastic mammary glands and nipples, poor perspiration, and bicornuate uterus in the mother. Endocrine studies performed for the underdeveloped external genitalia when the brothers were 11 6/12 and 7 2/12 years old, respectively, indicated low to low-normal responses of luteinizing hormone (LH) and follicle stimulating hormone (FSH) to gonadotropin releasing hormone stimulation tests (elder brother: LH = < 0.2 --> 2.2 IU/L, FSH = 0.6 --> 2.2 IU/L; younger brother: LH = < 0.2 --> 3.3 IU/L, FSH = 0.7 --> 4.4 IU/L) and normal testosterone responses to human gonadotropin stimulation tests (elder brother: < 0.5 --> 8.8 nmol/L; younger brother: < 0.5 --> 6.3 nmol/L). Testosterone enanthate therapy (25 mg/dose IM twice) was effective in the brothers, with penile length increase being similar between the brothers (approximately 5 mm/dose) and 23 age-matched boys with idiopathic micropenis (mean 4.4 mm/dose, range 2.5-7.5 mm/dose). Sequence analysis of the TBX3 gene showed a novel heterozygous nonsense mutation (A817T, K273X) in exon 4 of the three patients. The results are consistent with the previous finding that UMS is caused by haploinsufficiency of TBX3, and imply that mild gonadotropin deficiency may be the primary cause for underdeveloped external genitalia in males with UMS.

Comprehensive next-generation sequencing analyses of hypoparathyroidism: identification of novel GCM2 mutations.

CONTEXT: In most patients with hypoparathyroidism (HP), the etiology is not defined clinically. Eight genes (AIRE, CASR, CLDN16, GATA3, GCM2, PTH, TBCE, and TRPM6) are known to be responsible genes associated with HP; however, no previous study has screened the eight responsible genes comprehensively in HP patients. OBJECTIVES: This study was conducted to determine the genetic defect in HP patients. We also described clinical and molecular findings of two HP patients with novel GCM2 mutations. SUBJECTS AND METHODS: We enrolled 20 nonconsanguineous Japanese patients with child-onset permanent HP without 22q11 deletion. Mutations and genomic rearrangements involving the eight genes were screened by targeted next-generation sequencing (NGS). We also screened genetic rearrangements by array comparative genomic hybridization (aCGH) in the mutation-negative patients. A putative deletion, which was suspected by NGS, was additionally analyzed by droplet digital PCR (ddPCR) and junction PCR. Identified novel nucleotide-level GCM2 mutants were characterized in vitro. RESULTS: We identified seven patients with a single gene disorder, including a CASR mutation, GATA3 mutations, and novel GCM2 mutations (R367Tfs*15, T370M, and the deletion encompassing exon 1). This submicroscopic deletion, which had been suspected by NGS, could not be detected by aCGH and was confirmed by ddPCR and junction PCR. Functional studies of R367Tfs*- and T370M-GCM2 demonstrated a reduction of target gene transactivation in both. CONCLUSIONS: Using comprehensive NGS analyses, we identified the genetic defect in 35% of HP patients in our cohort and discovered novel GCM2 mutations including submicroscopic deletion that was undetectable by aCGH.

The contribution of serine 194 phosphorylation to steroidogenic acute regulatory protein function.

The steroidogenic acute regulatory protein (StAR) facilitates the delivery of cholesterol to the inner mitochondrial membrane, where the cholesterol side-chain cleavage enzyme catalyzes the initial step of steroid hormone biosynthesis. StAR was initially identified in adrenocortical cells as a phosphoprotein, the expression and phosphorylation of which were stimulated by corticotropin. A number of in vitro studies have implicated cAMP-dependent phosphorylation at serine 194 (S194, S195 in human StAR) as an important residue for StAR activity. To explore the importance of S194 phosphorylation in StAR function in vivo, we developed a transgenic model using a bacterial artificial chromosome expressing either wild-type (WT) StAR or StAR mutation S194A to rescue StAR knockout (KO) mice. Despite StAR protein expression comparable to or higher than amounts seen with control animals or rescue with WT StAR, S194A StAR did not rescue the neonatal lethality and only partially rescued the sex reversal in male mice observed uniformly in StAR KO mice. Like the StAR KO mice, the adrenal cortex and testicular Leydig cells contained abundant lipid deposits when stained with oil red O. Adrenal StAR from S194A rescue animals lacks an acidic species, which appears upon corticotropin stimulation in animals rescued with WT StAR, consistent with defective StAR phosphorylation. These findings demonstrate that S194 is an essential residue for normal StAR function in the adrenal cortex and testes of mice.

A 2.0 Mb microdeletion in proximal chromosome 14q12, involving regulatory elements of FOXG1, with the coding region of FOXG1 being unaffected, results in severe developmental delay, microcephaly, and hypoplasia of the corpus callosum.

We identified 2.0 Mb of a novel deletion on chromosome 14q12, involving 8 genes and putative regulatory elements of FOXG1 by array CGH in a patient with severe growth and psychomotor retardation, hypotonia, microcephaly, dysmorphic face, and hypoplasia of the corpus callosum. Case of a submicroscopic 14q12 deletion, involving regulatory elements of FOXG1, with the coding region of FOXG1 being unaffected, is extremely rare. Using fibroblast cell line established from the patient, we showed that the expression level of FOXG1 in our patient was decreased. Our finding provides additional evidence that not only over-dosage of FOXG1 as previously mentioned, under-dosage of FOXG1 is also associated with phenotype, overlapping between congenital variant of Rett syndrome with FOXG1 mutations and 14q12 microdeletion, not including the coding region of FOXG1. Though the gene dosage of FOXG1 appears to be critical for the normal development of brain, the complex mechanism of its regulation of gene expression remains to be elucidated.