Kei Takasawa

FOXL2 transcriptionally represses Sf1 expression by antagonizing WT1 during ovarian development in mice

Steroidogenic factor 1 (SF1; Ad4BP/NR5A1) plays key roles in gonadal development. Initially, the Sf1 gene is expressed in mouse fetal gonads of both sexes, but later is up‐regulated in testes and down‐regulated in ovaries. While Sf1 expression is activated and maintained by Wilms tumor 1 (WT1) and LIM homeobox 9 (LHX9), the mechanism of sex‐specific regulation remains unclear. We hypothesized that Sf1 is repressed by the transcription factor Forkhead box L2 (FOXL2) during ovarian development. In an in vitro system (TM3 cells), up‐regulation of Sf1 by the WT1 splice variant WT1‐KTS was antagonized by FOXL2, as determined by quantitative RT‐PCR. Using reporter assays, we localized the Sf1 proximal promoter region involved in this antagonism to a 674‐bp interval. A conserved FOXL2 binding site was identified in this interval by in vitro chromatin immunoprecipitation. Introducing mutations into this site abolished negative regulation by FOXL2 in reporter assays. Finally, in Foxl2‐null mice, Sf1 expression was increased 2‐fold relative to wild‐type XX fetal gonads. Our results support the hypothesis that FOXL2 negatively regulates Sf1 expression by antagonizing WT1‐KTS during early ovarian development in mice.—Takasawa, K., Kashimada, K., Pelosi, E., Takagi, M., Morio, T., Asahara, H., Schlessinger, D., Mizutani, S., Koopman, P. FOXL2 transcriptionally represses Sf1 expression by antagonizing WT1 during ovarian development in mice. FASEB J. 28, 2020–2028 (2014). www.fasebj.org

Identical NR5A1 Missense Mutations in Two Unrelated 46,XX Individuals with Testicular Tissues

The role of monogenic mutations in the development of 46,XX testicular/ovotesticular disorders of sex development (DSD) remains speculative. Although mutations in NR5A1 are known to cause 46,XY gonadal dysgenesis and 46,XX ovarian insufficiency, such mutations have not been implicated in testicular development of 46,XX gonads. Here, we identified identical NR5A1 mutations in two unrelated Japanese patients with 46,XX testicular/ovotesticular DSD. The p.Arg92Trp mutation was absent from the clinically normal mothers and from 200 unaffected Japanese individuals. In silico analyses scored p.Arg92Trp as probably pathogenic. In vitro assays demonstrated that compared with wild‐type NR5A1, the mutant protein was less sensitive to NR0B1‐induced suppression on the SOX9 enhancer element. Other sequence variants found in the patients were unlikely to be associated with the phenotype. The results raise the possibility that specific mutations in NR5A1 underlie testicular development in genetic females.

The p.R92W variant of NR5A1/Nr5a1 induces testicular development of 46,XX gonads in humans, but not in mice: phenotypic comparison of human patients and mutation-induced mice

NR5A1 is the key regulator of adrenal and gonadal development in both humans and mice. Recently, a missense substitution in human NR5A1, p.R92W, was shown to underlie gonadal dysgenesis in genetic males and testicular formation in genetic females. Here, we investigated the phenotypic effects of the p.R92W mutation on murine development. Mice carrying the p.R92W mutation manifested a similar but milder phenotype than that of the previously described Nr5a1 knockout mice. Importantly, mutation-positive XX mice showed no signs of masculinization. These results, together with prior observations, indicate that the p.R92W mutation in NR5A1/Nr5a1 encodes unique molecules that disrupt male gonadal development in both humans and mice and induces testicular formation specifically in human females. Our findings provide novel insights into the conservation and divergence in the molecular networks underlying mammalian sexual development.

Cause of acute encephalitis/encephalopathy in Japanese children diagnosed by a rapid and comprehensive virological detection system and differences in their clinical presentations

BACKGROUND Acute encephalitis/encephalopathy (AE/E) is a rare and severe complication of common childhood infections; however, a treatment strategy based on clinical and pathological evidence has not been established. METHODS The clinical data and aetiological results using a rapid and comprehensive virological detection system of 62 Japanese children diagnosed with AE/E from 2010 to 2014 were collected. We assessed clinical differences between causes and effectiveness of our multiplex PCR system to establish a pathogen-based treatment strategy for AE/E. RESULTS Suspected causes were detected in 84% of patients, and our multiplex PCR system contributed to diagnosing 38% of the patients. Furthermore, a negative virus PCR might be important for inferring underlying disease. Most cases were triggered by human herpes virus (HHV) 6/7 (32%) and influenza virus (24%). The causes of AE/E depended on age (p=0.00089) but not on sex (p=0.94). The median age of HHV6/7-associated AE/E was 2.3years, which is lower than the median ages of AE/E associated with other viruses. Major initial treatments were pulse steroid therapy (83.9%) and acyclovir (71%). Most of the patients in this study had good prognoses: 77% recovered without neurological sequalae. CONCLUSIONS Our virological detection system was useful for detecting the cause of AE/E, and may also contribute to construction of pathogen-based treatment strategies for AE/E. Our data indicated the possibility that early intervention with pulse steroid therapy could be effective for treating AE/E. Further investigation for selection of antiepileptic drugs and additional therapies might be required to prevent progression of AE/E.

Molecular mechanisms of insulin resistance in 2 cases of primary insulin receptor defect-associated diseases

Defects of the insulin receptor gene ( INSR ) cause wide spectra of congenital insulin resistance. Monoallelic defects result in milder insulin‐resistant diabetes mellitus with acanthosis nigricans (IRAN, type A). Whereas, leprechaunism (Donahue syndrome), the most severe condition with lethality during the infantile period is caused by biallelic defects of INSR .

Two novel HSD3B2 missense mutations with diverse residual enzymatic activities for Δ5‐steroids

Classical 3β‐hydroxysteroid dehydrogenase (3β‐HSD) deficiency (3β‐HSDD) is caused by loss‐of‐function mutations in the HSD3B2 gene encoding type II 3β‐HSD, which has a key role in steroid biosynthesis, converting Δ5‐steroids to Δ4‐steroids in adrenal glands and gonads.

Clinical characteristics of adolescent cases with Type A insulin resistance syndrome caused by heterozygous mutations in the β-subunit of the insulin receptor (INSR) gene: Type A insulin resistance in adolescents

Type A insulin resistance (IR) is a rare form of severe congenital IR that is frequently caused by heterozygous mutations in the insulin receptor (INSR) gene. Although Type A IR requires appropriate intervention from the early stages of diabetes, proper diagnosis of this disease is challenging, and accumulation of cases with detailed clinical profiles and genotypes is required.

Incidence and Characteristics of Adrenal Crisis in Children Younger than 7 Years with 21-Hydroxylase Deficiency: A Nationwide Survey in Japan

Background/Aims: We aimed to evaluate the incidence and characteristics of adrenal crisis in Japanese children with 21-hydroxylase deficiency (21-OHD). Methods: We conducted a retrospective nationwide survey for the councilors of the Japanese Society for Pediatric Endocrinology (JSPE) regarding adrenal crisis in children under 7 years with 21-OHD, admitted to hospitals from 2011 through 2016. We defined adrenal crisis as the acute impairment of general health due to glucocorticoid deficiency with at least two of symptoms, signs, or biochemical abnormalities. Results: The councilors of the JSPE in 83 institutions responded to this survey (response rate, 60.1%). Data analyses of 378 patients with 1,101.4 person-years (PYs) revealed that 67 patients (17.7%) experienced at least 1 episode of hospital admission for adrenal crisis at the median age of 2 years. The incidence of adrenal crisis was calculated as 10.9 per 100 PYs (95% confidence interval [CI] 9.6–12.2). Infections were the most common precipitating factors, while no factor was observed in 12.5%. Hypoglycemia occurred concomitantly in 27.4%. One patient died from severe hypoglycemia, resulting in a mortality rate of 0.09 per 100 PYs (95% CI 0.0–0.2). Conclusion: Adrenal crisis is not rare and can be accompanied by disastrous hypoglycemia in children with 21-OHD.

Risk of coronary artery lesions in young infants with Kawasaki disease: need for a new diagnostic method

To examine clinical characteristics of Kawasaki disease (KD) in infants younger than 3 months of age and to develop a method for detecting KD in febrile infants.

Abdominal paraganglioma in a young woman with 1p36 deletion syndrome

1p36 deletion syndrome is the most common terminal deletion syndrome, and the genomic regions that contribute to specific 1p36 deletion syndrome‐related phenotypes were recently identified. Deletions in the 1p36 region have been documented in various tumor tissues, which indicates correlation between loss of heterozygosity of 1p36 and tumor development, and the existence of tumor suppressors in this region. Therefore, it was suspected that patients with 1p36 deletion syndrome have a higher risk of tumor development; however, only a few child cases of neuroblastoma with 1p36 deletion syndrome have been reported. We report the first case of 1p36 deletion syndrome with paraganglioma (PGL) and include genetic investigation. The 24‐year‐old woman with 1p36 deletion syndrome had severe intellectual disability, dilated cardiomyopathy, and distinct dysmorphic features, and presented with persistent vomiting accompanied by hypertension (178/115 mmHg). Abdominal CT revealed a 40 × 50 mm retroperitoneal mass and substantial elevations of plasma and urine norepinephrine (15.4 nmol/L and 1022 µmol/mol creatinine, respectively); abnormal uptake of 123I‐MIBG in the tumor led to PGL diagnosis. The patient was not able to have surgery because of substantial surgical risks; however, a combination of α‐ and β‐blockade was effective for blood pressure control. Array CGH revealed a deletion over 4.5 Mb, from the 1p telomere but excluding the SDHB region. Comprehensive mutational analysis of PGL‐associated genes (RET, VHL, TMEM127, MAX, and SDHA/B/C/D) was negative. These results indicate that the germline 1p36 deletion might be “1st hit” of tumor development, and PGL might be a novel complication of 1p36 deletion syndrome.