Congenital anaemia associated with loss-of-function variants in DNA polymerase epsilon 1.

DNA polymerase epsilon (Pol ε), a component of the core replisome, is involved in DNA replication. Although genetic defects of Pol ε have been reported to cause immunodeficiency syndromes, its role in haematopoiesis remains unknown. Here, we identified compound heterozygous variants (p.[Asp1131fs];[Thr1891del]) in POLE, encoding Pol ε catalytic subunit A (POLE1), in siblings with a syndromic form of severe congenital transfusion-dependent anaemia. In contrast to Diamond-Blackfan anaemia, marked reticulocytopenia or marked erythroid hypoplasia was not found. Their bone marrow aspirates during infancy revealed erythroid dysplasia with strongly positive TP53 in immunostaining. Repetitive examinations demonstrated trilineage myelodysplasia within 2 years from birth. They had short stature and facial dysmorphism. HEK293 cell-based expression experiments and analyses of patient-derived induced pluripotent stem cells (iPSCs) disclosed a reduced mRNA level of Asp1131fs-POLE1 and defective nuclear translocation of Thr1891del-POLE1. Analysis of iPSCs showed compensatory mRNA upregulation of the other replisome components and increase of the TP53 protein, both suggesting dysfunction of the replisome. We created Pole-knockout medaka fish and found that heterozygous fishes were viable, but with decreased RBCs. Our observations expand the phenotypic spectrum of the Pol ε defect in humans, additionally providing unique evidence linking Pol ε to haematopoiesis.

Mismatch between fetal sexing and birth phenotype: a case of complete androgen insensitivity syndrome.

With advancing maternal age, the number of prenatal genetic tests is increasing in many countries. Prenatal genetic tests, such as amniocentesis, chorionic villus sampling and non-invasive prenatal testing, can disclose fetal chromosomal sex, although these tests were originally designed to prenatally diagnose chromosomal aneuploidies, such as trisomy 21, 18 and 13. Complete androgen insensitivity syndrome (CAIS) is an X-linked recessive disorder caused by an androgen receptor dysfunction leading to hormone resistance. The affected individuals are genetic males as shown by 46,XY but present complete female external genitalia and normal breast development at puberty albeit without menstruation. CAIS is commonly diagnosed in adolescence based on primary amenorrhea or in childhood based on inguinal hernia or testis-like masses in the inguinal region. In the present report, we describe a baby in whom CAIS was diagnosed immediately after birth based on a mismatch between the fetal karyotype detected by amniocentesis and the external genitalia phenotype at birth. We speculate that the increase in the number of prenatal genetic tests is contributing to the early detection of 46,XY disorders of sex development, especially those previously called complete sex reversal, which is supposedly diagnosed during childhood or adolescence. Hence, it is necessary to understand the disease-specific hormone profile at each developmental stage for accurate diagnosis.

Temple syndrome: comprehensive molecular and clinical findings in 32 Japanese patients.

PurposeTemple syndrome (TS14) is a rare imprinting disorder caused by aberrations at the 14q32.2 imprinted region. Here, we report comprehensive molecular and clinical findings in 32 Japanese patients with TS14.MethodsWe performed molecular studies for TS14 in 356 patients with variable phenotypes, and clinical studies in all TS14 patients, including 13 previously reported.ResultsWe identified 19 new patients with TS14, and the total of 32 patients was made up of 23 patients with maternal uniparental disomy (UPD(14)mat), six patients with epimutations, and three patients with microdeletions. Clinical studies revealed both Prader-Willi syndrome (PWS)-like marked hypotonia and Silver-Russell syndrome (SRS)-like phenotype in 50% of patients, PWS-like hypotonia alone in 20% of patients, SRS-like phenotype alone in 20% of patients, and nonsyndromic growth failure in the remaining 10% of patients in infancy, and gonadotropin-dependent precocious puberty in 76% of patients who were pubescent or older.ConclusionThese results suggest that TS14 is not only a genetically diagnosed entity but also a clinically recognizable disorder. Genetic testing for TS14 should be considered in patients with growth failure plus both PWS-like hypotonia and SRS-like phenotypes in infancy, and/or precocious puberty, as well as a familial history of Kagami-Ogata syndrome due to maternal microdeletion at 14q32.2.

Heterozygous carriers of succinyl-CoA:3-oxoacid CoA transferase deficiency can develop severe ketoacidosis.

Succinyl-CoA:3-oxoacid CoA transferase (SCOT, gene symbol OXCT1) deficiency is an autosomal recessive disorder in ketone body utilization that results in severe recurrent ketoacidotic episodes in infancy, including neonatal periods. More than 30 patients with this disorder have been reported and to our knowledge, their heterozygous parents and siblings have had no apparent ketoacidotic episodes. Over 5 years (2008-2012), we investigated several patients that presented with severe ketoacidosis and identified a heterozygous OXCT1 mutation in four of these cases (Case1 p.R281C, Case2 p.T435N, Case3 p.W213*, Case4 c.493delG). To confirm their heterozygous state, we performed a multiplex ligation-dependent probe amplification analysis on the OXCT1 gene which excluded the presence of large deletions or insertions in another allele. A sequencing analysis of subcloned full-length SCOT cDNA showed that wild-type cDNA clones were present at reasonable rates to mutant cDNA clones. Over the following 2 years (2013-2014), we analyzed OXCT1 mutations in six more patients presenting with severe ketoacidosis (blood pH ≦7.25 and total ketone body ≧10 mmol/L) with non-specific urinary organic acid profiles. Of these, a heterozygous OXCT1 mutation was found in two cases (Case5 p.G391D, Case6 p.R281C). Moreover, transient expression analysis revealed R281C and T435N mutants to be temperature-sensitive. This characteristic may be important because most patients developed ketoacidosis during infections. Our data indicate that heterozygous carriers of OXCT1 mutations can develop severe ketoacidotic episodes in conjunction with ketogenic stresses.

Portosystemic shunt as a cause of congenital hyperinsulinemic hypoglycemia.

Congenital hyperinsulinemic hypoglycemia (CHH) is characterized by the inappropriate secretion of insulin from pancreatic beta cells in the presence of hypoglycemia. We herein describe the case of a 5-month-old boy with CHH due to congenital portosystemic shunt (CPSS). Insulin secreted from pancreatic beta cells flows into the portal vein and is first metabolized in the liver. First-pass elimination of insulin in the liver leads to great decrease in insulin concentration by approximately 40-80% in humans. CPSS accounts for a large quantity of insulin delivery into the systemic circulation due to the lack of hepatic first-pass elimination. Hypoglycemia can result from consistently high levels of insulin after reaching normal glucose level. CPSS therefore should be considered as a rare cause of CHH, especially in the case of post-prandial hyperinsulinemic hypoglycemia.

Systematic molecular analyses of SHOX in Japanese patients with idiopathic short stature and Leri-Weill dyschondrosteosis.

The etiology of idiopathic short stature (ISS) and Leri-Weill dyschondrosteosis (LWD) in European patients is known to include SHOX mutations and copy-number variations (CNVs) involving SHOX and/or the highly evolutionarily conserved non-coding DNA elements (CNEs) flanking the gene. However, the frequency and types of SHOX abnormalities in non-European patients and the clinical importance of mutations in the CNEs remains to be clarified. Here, we performed systematic molecular analyses of SHOX for 328 Japanese patients with ISS or LWD. SHOX abnormalities accounted for 3.8% of ISS and 50% of LWD cases. CNVs around SHOX were identified in 16 cases, although the ~47 kb deletion frequently reported in European patients was absent in our cases. Probably damaging mutations and benign/silent substitutions were detected in four cases, respectively. Although CNE-linked substitutions were detected in 15 cases, most of them affected poorly conserved nucleotides and were shared by unaffected individuals. These results suggest that the frequency and mutation spectrum of SHOX abnormalities are comparable between Asian and European patients, with the exception of a European-specific downstream deletion. Furthermore, this study highlights the clinical importance and genetic heterogeneity of the SHOX-flanking CNVs, and indicates a limited clinical significance of point mutations in the CNEs.

Extra-adrenal induction of Cyp21a1 ameliorates systemic steroid metabolism in a mouse model of congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase (21-OH) deficiency (21-OHD) is an autosomal recessive disorder, in which CYP21A2 mutations or deletions result in underproduction of glucocorticoid and mineralocorticoid, and overproduction of androgens. Patients with CAH are treated with oral steroid supplementation, but optimal control of blood steroid levels remains difficult. Thus, new therapeutic approaches are still needed. Previously, adenovirus-mediated administration of human CYP21A2 to adrenal glands rescued the phenotype of a mouse model of 21-OHD. In this study, we examined whether transduction of murine Cyp21a1 in extra-adrenal tissues could rescue steroid metabolism in 21-OHD mice. We transduced primary fibroblasts obtained from 21-OHD mice with a retroviral vector containing Cyp21a1. In vitro assays demonstrated that Cyp21a1-expressing fibroblasts can uptake progesterone from the culture media, convert it to deoxycorticosterone (DOC), and subsequently release DOC back into the media. Autotransplantation of Cyp21a1-expressing fibroblasts into the subcutaneous tissues of the back resulted in a significant reduction in the serum progesterone/DOC ratio in four of six 21-OHD mice at 4 weeks after injection. We also directly injected an adeno-associated viral vector containing Cyp21a1 into the thigh muscles of 21-OHD mice. Serum progesterone/DOC ratios were markedly reduced in all four animals at 4 weeks after injection. These results indicate that extra-adrenal induction of Cyp21a1 ameliorates steroid metabolism in 21-OHD mice. This study suggests a novel therapeutic strategy for congenital adrenal hyperplasia, which warrants further investigations.

Rare pseudoautosomal copy-number variations involving SHOX and/or its flanking regions in individuals with and without short stature.

Pseudoautosomal region 1 (PAR1) contains SHOX, in addition to seven highly conserved non-coding DNA elements (CNEs) with cis-regulatory activity. Microdeletions involving SHOX exons 1-6a and/or the CNEs result in idiopathic short stature (ISS) and Leri-Weill dyschondrosteosis (LWD). Here, we report six rare copy-number variations (CNVs) in PAR1 identified through copy-number analyzes of 245 ISS/LWD patients and 15 unaffected individuals. The six CNVs consisted of three microduplications encompassing SHOX and some of the CNEs, two microduplications in the SHOX 3'-region affecting one or four of the downstream CNEs, and a microdeletion involving SHOX exon 6b and its neighboring CNE. The amplified DNA fragments of two SHOX-containing duplications were detected at chromosomal regions adjacent to the original positions. The breakpoints of a SHOX-containing duplication resided within Alu repeats. A microduplication encompassing four downstream CNEs was identified in an unaffected father-daughter pair, whereas the other five CNVs were detected in ISS patients. These results suggest that microduplications involving SHOX cause ISS by disrupting the cis-regulatory machinery of this gene and that at least some of microduplications in PAR1 arise from Alu-mediated non-allelic homologous recombination. The pathogenicity of other rare PAR1-linked CNVs, such as CNE-containing microduplications and exon 6b-flanking microdeletions, merits further investigation.

A thyroid adenoma in a pubertal male with thyroxine-binding globulin deficiency.

Complete deficiency of thyroxin-binding globulin (TBG-CD) is not commonly associated with clinical symptoms, and little is known about thyroid tumors associated with TBG-CD. We present a case report of an asymptomatic follicular adenoma that spontaneously shrank in a patient with TBG-CD. A previously healthy 13-yr-old male presented with a diffusely swollen thyroid gland. Thyroid function tests revealed low total thyroxin and TBG concentrations, indicating a TBG deficiency. Ultrasonography revealed a mildly swollen thyroid gland with a nodule (14 × 12 × 19 mm) in the left lobe. Genetic analysis of peripheral blood revealed a previously reported SERPINA7 variant, which resulted in complete loss of TBG function. The nodule was identified as a follicular adenoma using fine-needle aspiration. Subsequently, the adenoma shrank without treatment. This pubertal case suggests that careful observation with ultrasonography is warranted for follicular adenoma in patients with TBG deficiency and that treatment may not be required.

Expression levels and DNA methylation profiles of the growth gene SHOX in cartilage tissues and chondrocytes.

All attempts to identify male-specific growth genes in humans have failed. This study aimed to clarify why men are taller than women. Microarray-based transcriptome analysis of the cartilage tissues of four adults and chondrocytes of 12 children showed that the median expression levels of SHOX, a growth gene in the pseudoautosomal region (PAR), were higher in male samples than in female samples. Male-dominant SHOX expression was confirmed by quantitative RT-PCR for 36 cartilage samples. Reduced representation bisulfite sequencing of four cartilage samples revealed sex-biased DNA methylation in the SHOX-flanking regions, and pyrosequencing of 22 cartilage samples confirmed male-dominant DNA methylation at the CpG sites in the SHOX upstream region and exon 6a. DNA methylation indexes of these regions were positively correlated with SHOX expression levels. These results, together with prior findings that PAR genes often exhibit male-dominant expression, imply that the relatively low SHOX expression in female cartilage tissues reflects the partial spread of X chromosome inactivation into PAR. Altogether, this study provides the first indication that sex differences in height are ascribed, at least in part, to the sex-dependent epigenetic regulation of SHOX. Our findings deserve further validation.

Comparison of physician- and self-assessed pubertal onset in Japanese children.

Introduction: Physical examinations to assess pubertal development are challenging in large epidemiological surveys. This study aimed to assess the reliability of judgment of pubertal onset in Japanese children by the original pubertal self-assessment sheet. Methods: A total of 144 children aged 10 or 12 years were recruited between March 2019 and September 2020 from the pediatric endocrine outpatient clinics of participating institutions. Agreement between the physician- and participantassessed pubertal onsets was determined using unweighted kappa (UK) and Gwet's agreement coefficient (AC1). Results: The physician's assessment of pubertal onset was in slight agreement with that of the self-assessment sheet in 10-year-old boys (UK: 0.23 and AC1: 0.14), whereas the agreement between the physician's assessment and self-assessment sheet results was good and the physician's assessment was fair (UK: 0.64 and AC1: 0.94) in 12-year-old boys. The physician's assessment of pubertal onset were in good and moderate agreement with the self-assessment sheet in 10-year-old girls (UK/AC1: 0.74/0.78, respectively). In 12-year-old girls, although it showed poor agreement with UK (0.46), there was a very good agreement with AC1 (0.88). Conclusions: Although self-assessment of breast development was in good agreement with that of the physician's assessment for determining pubertal onset in girls, large-scale epidemiological studies are difficult to conduct for adolescent boys, especially for those in the early pubertal stage.

Living-donor liver transplantation for propionic acidemia.

Propionic acidemia is a rare autosomal recessive disorder affecting the catabolism of branched-chain amino acids because of a genetic defect in PCC. Despite the improvements in medical treatment with protein restriction, sufficient caloric intake, supplementation of l-carnitine, and metronidazole, patients with the severe form of propionic acidemia have life-threatening metabolic acidosis, hyperammonemia, and cardiomyopathy, which results in serious neurologic sequelae and sometimes death. This study retrospectively reviewed three children with neonatal-onset propionic acidemia who received LDLT. Between November 2005 and December 2010, 148 children underwent LDLT, with an overall patient survival of 90.5%, in our center. Three patients were indicated for transplantation because of propionic acidemia. All recipients achieved a resolution of metabolic derangement and better quality of life with protein restriction and medication, although urine methylcitrate and serum propionylcarnitine levels did not decrease markedly. LT can reduce the magnitude of progressive cardiac/neurologic disability as a result of poor metabolic control. Further evaluation is therefore required to determine the long-term suitability of this treatment modality.

Novel non-stop variant of the NR0B1 gene in two siblings with adrenal hypoplasia congenita.

OBJECTIVES: Mutations in the dosage-sensitive sex reversal-AHC critical region on the X chromosome, gene 1 (DAX-1, officially NR0B1), cause X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). Salt-losing adrenal insufficiency usually occurs during the neonatal period or early childhood. We report a novel non-stop variant of NR0B1 in two siblings and their unusual clinical course. CASE PRESENTATION: The proband was a boy who presented with an unusual form of AHC with neonatal onset of growth failure and mild salt loss, but without cutaneous pigmentation or plasma ACTH elevation. His 4-year-old elder brother had been growing healthily, but carried an AHC diagnosis. A non-stop variant of NR0B1 (p.*471K) was demonstrated in the patients and their mother. CONCLUSIONS: We identified a novel non-stop variant of NR0B1 in two siblings. Mild salt loss associated with hyperkalemia is a crucial diagnostic clue for AHC, even without apparent symptoms of glucocorticoid deficiency.

Adeno-Associated Virus-Mediated Gene Therapy for Patients' Fibroblasts, Induced Pluripotent Stem Cells, and a Mouse Model of Congenital Adrenal Hyperplasia.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder caused by steroidogenic enzymes containing monogenetic defects. Most steroidogenic enzymes are cytochrome P450 groups that can be categorized as microsomal P450s, including 21-hydroxylase and 17α-hydroxylase/17,20 lyase, and mitochondrial P450s, including 11ß-hydroxylase. It has been shown that ectopic administration of Cyp21a1 ameliorates steroid metabolism in 21-hydroxylase-deficient mice. However, the effectiveness of this approach for mitochondrial P450 has not yet been evaluated. In this study, primary fibroblasts from patients with 21-hydroxylase deficiency (CYP21A2D) (n = 4), 17α-hydroxylase/17,20 lyase deficiency (CYP17A1D) (n = 1), and 11ß-hydroxylase deficiency (CYP11B1D) (n = 1) were infected with adeno-associated virus type 2 (AAV2) vectors. Steroidogenic enzymatic activity was not detected in the AAV2-infected CYP11B1D fibroblasts. Induced pluripotent stem cells (iPSCs) of CYP11B1D were established and differentiated into adrenocortical cells by induction of the NR5A1 gene. Adrenocortical cells established from iPSCs of CYP11B1D (CYP11B1D-iPSCs) were infected with an AAV type 9 (AAV9) vector containing CYP11B1 and exhibited 11ß-hydroxylase activity. For an in vivo evaluation, we knocked out Cyp11b1 in mice by using the CRISPR/Cas9 method. Direct injection of Cyp11b1-containing AAV9 vectors into the adrenal gland of Cyp11b1-deficient mice significantly reduced serum 11-deoxycorticosterone/corticosterone ratios at 4 weeks after injection and the effect was prolonged for up to 12 months. This study indicated that CYP11B1D could be ameliorated by gene induction in the adrenal glands, which suggests that a defective-enzyme-dependent therapeutic strategy for CAH would be required. Defects in microsomal P450, including CYP21A2D and CYP17A1D, can be treated with extra-adrenal gene induction. However, defects in mitochondrial P450, as represented by CYP11B1D, may require adrenal gene induction.

A novel mutation (c.951C>T) in an exonic splicing enhancer results in exon 10 skipping in the human mitochondrial acetoacetyl-CoA thiolase gene.

Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inherited disorder affecting isoleucine catabolism and ketone body metabolism. A Japanese female developed a severe ketoacidotic attack at the age of 7 months. Urinary organic acid analysis showed elevated excretion of 2-methyl-3-hydroxybutyrate but not tiglylglycine. She was diagnosed as having T2 deficiency by enzyme assay using fibroblasts. Mutation analysis revealed a compound heterozygote of c.556G>T(D186Y) and c.951C>T(D317D). Since c.951C>T does not cause amino acid change, we performed cDNA analysis and found that exon 10 skipping had occurred in the c.951C>T allele. A computer search using an ESE finder showed that an exonic splicing enhancer sequence, SF2/ASF, was located in CTGA(951)CGC. We hypothesized that the exonic splicing enhancer is necessary for accurate splicing since the first nucleotide of exon 10 is C, which weakens the splice acceptor site of intron 9. We made a mini gene construct including exon 9-truncated intron 9-exon 10-truncated intron 10-exon 11 for a splicing experiment. We also made three mutant constructs which alter the SF2/ASF site (947C>T, 951C>T, 952G>A). An min-gene splicing experiment clearly showed that exon 10 skipping was induced in all three mutant constructs. Moreover, additional substitution of G for C at the first nucleotide of exon 10 resulted in normal splicing in these three mutants. These results confirmed that c.951C>T diminished the effect of the exonic splicing enhancer and caused exon 10 skipping.

Living-donor liver transplantation for carbamoyl phosphate synthetase 1 deficiency.

CPS1 is a mitochondrial matrix enzyme that catalyzes the first committed step of the urea cycle, the primary system for removing nitrogen produced by protein metabolism using N-acetylglutamate. Patients with CPS1 deficiency have severe hyperammonemia that results in serious neurologic sequelae and sometimes death. LT has been indicated for neonatal-onset CPS1 deficiency. This study retrospectively reviewed five children with a diagnosis of CPS1 deficiency who underwent LDLT from heterozygous donors. Between November 2005 and May 2010, 124 children underwent LDLT with an overall patient and graft survival of 91.0%. Five patients were indicated for LDLT because of CPS1 deficiency. All recipients achieved resolution of their metabolic derangement, without donor complication, with a normal feeding regimen without medication for their original metabolic liver disease. LDLT, even from heterozygous donors, appears to be a feasible option, associated with a better quality of life for treating patients with CPS1 deficiency. Long-term observation may therefore be necessary to collect sufficient data to confirm the efficacy of this treatment modality.

Living donor liver transplantation for glycogen storage disease type Ib.

Glycogen storage disease type 1b (GSD-1b) is due to an autosomal recessive inborn error of carbohydrate metabolism caused by defects in glucose-6-phosphatase translocase. Patients with GSD-1b have severe hypoglycemia with several clinical manifestations of hepatomegaly, obesity, a doll-like face, and neutropenia. Liver transplantation has been indicated for severe glucose intolerance. This study retrospectively reviewed 4 children with a diagnosis of GSD-1b who underwent living-donor liver transplantation (LDLT). Between November 2005 and June 2008, 96 children underwent LDLT with overall patient and graft survival of 92.3%. Of these, 4 (4.2%) were indicated for GSD-1b. All patients are doing well with an excellent quality of life because of the stabilization of glucose intolerance, decreased hospital admission, and normalized neutrophil count. LDLT appears to be a feasible option and is associated with a better quality of life for patients with GSD-1b. Long-term observation may be necessary to collect sufficient data to confirm the efficacy of this treatment modality.

(Epi)genetic defects of MKRN3 are rare in Asian patients with central precocious puberty.

We sequenced MKRN3, the major causative gene of central precocious puberty in Western countries, in 24 Japanese or Chinese patients and examined the DNA methylation and copy-number statuses of this gene in 19 patients. We identified no (epi)genetic defects except for one previously reported mutation. These results, together with reports from Korea, indicate that MKRN3 defects are rare in Asian populations. The ethnic differences likely reflect Western country-specific founder mutations and the rarity of de novo mutations.

Functional missense and splicing variants in the retinoic acid catabolizing enzyme CYP26C1 in idiopathic short stature.

Height is a complex quantitative trait with a high heritability. Short stature is diagnosed when height is significantly below the average of the general population for that person's age and sex. We have recently found that the retinoic acid degrading enzyme CYP26C1 modifies SHOX deficiency phenotypes toward more severe clinical manifestations. Here, we asked whether damaging variants in CYP26C1 alone could lead to short stature. We performed exome and Sanger sequencing to analyze 856 individuals with short stature where SHOX deficiency was previously excluded. Three different damaging missense variants and one splicing variant were identified in six independent individuals; the functional significance of the identified variants was tested in vitro or in vivo using zebrafish as a model. The genetic and functional data reported here indicate that CYP26C1 represents a novel gene underlying growth disorders and that damaging variants in the absence of SHOX variants can lead to short stature.

Nonclassic steroid 21-hydroxylase deficiency due to a homozygous V281L mutation in CYP21A2 detected by the neonatal mass-screening program in Japan.

Since 1989, neonatal mass screening for congenital adrenal hyperplasia (CAH) has been carried out in Japan. The mass screening has detected not only the patients with the classic form of steroid 21-hydroxylase deficiency (21-OHD), but also those with the nonclassic (NC) form of 21-OHD, and the molecular basis in these patients has been elucidated. However, the homozygous V281L mutation in CYP21A2, the common mutation in the NC form in Caucasians, has not been described in Japanese patients, implying at least two possibilities; 1) the V281L mutation itself might be very rare in Japanese, and 2) nonclassic 21-OHD patients bearing the V281L mutation might be barely detectable by the mass-screening program, hence overlooked in Japan. In the present study, we describe a Brazilian girl with the NC form of 21-OHD, who was pointed out to have mildly elevated 17 alpha-hydroxyprogesterone in blood by the mass screening in Japan. Genetic analysis revealed that the patient was homozygous for the V281L mutation, and that the parents were heterozygous for the V281L mutation. Thus, the NC patients due to the homozygous V281L mutation can be detectable by the mass-screening program for CAH in Japan, and further accumulation and analysis of the NC patients should elucidate the frequency of the V281L allele in Japan.