Takao Togawa

Neurodevelopmental Outcomes at 18 Months’ Corrected Age of Infants Born at 22 Weeks of Gestation

Background: Increased survival rates for extremely low birth weight infants have been reported. However, survival rates and prognoses of extremely preterm infants, such as infants born at 22 weeks of gestation, are still poor. Objective: To investigate such infants’ long-term outcomes, developmental assessments were performed. Methods: Seven infants with gestational age of 22 weeks were delivered in our hospital from 2005 to 2008. One infant was a stillbirth despite resuscitation in the delivery room. Six infants, 4 boys and 2 girls, with a gestational age of 22 weeks (range 223/7–226/7 weeks), were admitted to the neonatal intensive care unit (NICU). Birth weights ranged from 514 to 710 g. None of the infants suffered from sepsis, necrotizing enterocolitis, or severe intraventricular hemorrhage. Results:The survival rate was 85.7% (6/7) as a percentage of deliveries and 100% (6/6) as a percentage of NICU admissions. None of the infants suffered from deafness, blindness, cerebral palsy, or epilepsy. Six infants were available for developmental assessments at 18 months’ corrected age. Three infants showed normal developmental quotients, and 3 infants showed developmental delay. Conclusion: In our study, all infants admitted to the NICU at a gestational age of 22 weeks were discharged from the hospital alive. This might suggest that infants after 22 weeks’ gestation be considered eligible for active treatment in Japan, though considering the size of the material, generalizibility of the results cannot be considered guaranteed.

A combination of genetic and biochemical analyses for the diagnosis of PI3K-AKT-mTOR pathway-associated megalencephaly

BackgroundConstitutive activation of the PI3K-AKT-mTOR pathway (mTOR pathway) underlies megalencephaly in many patients. Yet, prevalence of the involvement of the PI3K-AKT-mTOR pathway in patients with megalencephaly remains to be elucidated, and molecular diagnosis is challenging. Here, we have successfully established a combination of genetic and biochemical methods for diagnosis of mTOR pathway-associated megalencephaly, and have attempted to delineate the clinical characteristics of the disorder.MethodsThirteen patients with an increased head circumference and neurological symptoms participated in the study. To evaluate the activation of the mTOR pathway, we performed western blot analysis to determine the expression levels of phosphorylated S6 ribosomal protein (phospho-S6 protein) in lymphoblastoid cell lines from 12 patients. Multiplex targeted sequencing analysis for 15 genes involved in the mTOR pathway was performed on 12 patients, and whole-exome sequencing was performed on one additional patient. Clinical features and MRI findings were also investigated.ResultsWe identified pathogenic mutations in six (AKT3, 1 patient; PIK3R2, 2 patients; PTEN, 3 patients) of the 13 patients. Increased expression of phospho-S6 protein was demonstrated in all five mutation-positive patients in whom western blotting was performed, as well as in three mutation-negative patients. Developmental delay, dysmorphic facial features were observed in almost all patients. Syndactyly/polydactyly and capillary malformations were not observed, even in patients with AKT3 or PIK3R2 mutations. There were no common phenotypes or MRI findings among these patients.ConclusionsA combination of genetic and biochemical methods successfully identified mTOR pathway involvement in nine of 13 (approximately 70%) patients with megalencephaly, indicating a major contribution of the pathway to the pathogenesis of megalencephaly. Our combined approach could be useful to identify patients who are suitable for future clinical trials using an mTOR inhibitor.

Biallelic mutations in SZT2 cause a discernible clinical entity with epilepsy, developmental delay, macrocephaly and a dysmorphic corpus callosum

Mutations in SZT2 were first reported in 2013 as a cause of early-onset epileptic encephalopathy. Because only five reports have been published to date, the clinical features associated with SZT2 remain unclear. We herein report an additional patient with biallelic mutations in SZT2. The proband, a four-year-old girl, showed developmental delay and seizures from two years of age. Her seizures were not intractable and readily controlled by valproate. She showed mildly dysmorphic facies with macrocephaly, high forehead, and hypertelorism, and also had pectus carinatum. An EEG showed epileptic discharges which rarely occurred. A brain MRI revealed a short and thick corpus callosum. Whole-exome sequencing detected compound heterozygous biallelic mutations (c.8596dup (p.Tyr2866Leufs∗42) and c.2930-17_2930-3delinsCTCGTG) in SZT2, both of which were novel and predicted to be truncating. This case suggested a broad phenotypic spectrum arises from SZT2 mutations, forming a continuum from epileptic encephalopathy and severe developmental delay to mild intellectual disability without epilepsy. The characteristic thick and short corpus callosum observed in 7/8 cases with epilepsy, including the proband, but not in three non-syndromic cases, appears to be specific, and thus useful for indicating the possibility of SZT2 mutations. This feature has the potential to make loss of SZT2 a clinically discernible disorder despite a wide clinical spectrum.

Effects of 4‐phenylbutyrate therapy in a preterm infant with cholestasis and liver fibrosis

The bile salt export pump is expressed at the canalicular membrane of hepatocytes and mediates biliary excretion of bile salts. 4‐Phenylbutyrate (4 PB), a drug used to treat ornithine transcarbamylase deficiency, has been found to increase the hepatocanalicular expression of bile salt export pump. The beneficial effects of 4‐phenylbutyrate therapy have been reported for patients with progressive familial intrahepatic cholestasis, an inherited autosomal recessive liver disease. This is the first study to show the therapeutic effect of 4 PB in a preterm infant with cholestasis and liver fibrosis. The preterm infant had severe cholestasis with jaundice and failure to thrive refractory to ursodeoxycholic acid. Histology indicated giant cell hepatitis, cholestasis, and severe fibrosis. Bile salt export pump immunostaining showed lower expression than in a control. Oral 4 PB was started at a daily dose of 200 mg/kg/day. After the start of 4 PB therapy, cholestasis improved.

Single nucleotide polymorphisms in AGTR1, TFAP2B, and TRAF1 are not associated with the incidence of patent ductus arteriosus in Japanese preterm infants

Persistent patent ductus arteriosus (PDA) is a frequent complication in preterm infants. Single nucleotide polymorphisms (SNP) in several genes, including angiotensin II receptor, type 1 (AGTR1), transcription factor AP‐2 beta (TFAP2B) and tumor necrosis factor receptor‐associated factor 1 (TRAF1), have been reported to be associated with PDA in preterm infants. The aim of this study was to evaluate the relationships between PDA in preterm infants and polymorphisms in AGTR1, TFAP2B and TRAF1 in the Japanese population.

Nemaline myopathy with KLHL40 mutation presenting as congenital totally locked-in state

We report a case of nemaline myopathy with KLHL40 mutation, presenting as congenital totally locked-in state. At birth, a male patient developed hydrops fetalis, which was diagnosed based on the generalized edema and pleural effusion and could perform no significant spontaneous movements. His eyes were open, without blinking, and the eyeballs were locked in the midposition. He could not express his intentions by vocalization or moving his trunk, extremities, facial muscles, mouth, eyelids, or eyeballs in response to ambient events or personal interactions. Electrophysiological tests and neuroimaging revealed no evidence of visual or auditory impairment that might indicate a lack of sensory perception, and no evidence of impaired consciousness or intellectual disorder(s) that might prevent him from recognizing ambient events or expressing his intentions. He subsequently died at 4 years of age. Our case highlights the fact that severe congenital neuromuscular disorders can present as congenital totally locked-in state, and that special attention should be provided to these patients.

Clinical, Pathologic, and Genetic Features of Neonatal Dubin-Johnson Syndrome: A Multicenter Study in Japan

Objective To clarify the clinical, pathologic, and genetic features of neonatal Dubin‐Johnson syndrome. Study design Ten patients with neonatal Dubin‐Johnson syndrome were recruited from 6 pediatric centers in Japan between September 2013 and October 2016. Clinical and laboratory course, macroscopic and microscopic liver findings, and molecular genetic findings concerning ATP‐binding cassette subfamily C member 2 (ABCC2) were retrospectively and prospectively examined. Results All neonates exhibited cholestasis, evident as prolonged jaundice with or without acholic stools and elevations of serum direct bilirubin as well as &ggr;‐glutamyltransferase or total bile acids. Only 38% (3 of 8) of patients who underwent liver biopsy showed a grossly black liver or melanin‐like pigment deposits in hepatocytes; their biopsies were performed in early infancy. Immunohistochemically, all liver specimens showed no expression of multidrug resistance‐associated protein 2 but increased expression of the bile salt export pump protein. Homozygous or compound heterozygous pathogenic variants of ABCC2 were identified in all patients, representing 11 distinct pathogenic variants including 2 not previously reported. Conclusions Immunohistochemical staining of the liver for multidrug resistance‐associated protein 2 and molecular genetic analysis of ABCC2 are crucial for accurate diagnosis of neonatal Dubin‐Johnson syndrome.

Combined genetic analyses can achieve efficient diagnostic yields for subjects with Alagille syndrome and incomplete Alagille syndrome

We evaluated combined genetic analyses with targeted next‐generation sequencing (NGS), multiplex ligation probe amplification (MLPA) of Jagged1 (JAG1) genes and microarray comparative genomic hybridisation (CGH) in subjects with Alagille syndrome, incomplete clinical features of Alagille syndrome and biliary atresia.

Risk factors for early death in transient myeloproliferative disorder without phenotypic features of Down syndrome: a case report and literature review.

Not only in newborns with Down syndrome, but newborns without phenotypic features of Down syndrome also develop transient myeloproliferative disorder (TMD). In these cases, trisomy 21 and related chromosomal abnormalities are either constitutionally mosaic or limited to blood cells. Risk factors for early death of these patients are unknown so far. We here report a fatal case of TMD without phenotypic features of Down syndrome and review literature to identify risk factors associated with early death. Not only are gestational age and white blood cell count risk factors for early death in TMD with Down syndrome, but they also appear to be risk factors in TMD without Down syndrome.

Molecular genetic and clinical delineation of 22 patients with congenital hypogonadotropic hypogonadism.

Abstract Background: Congenital hypogonadotropic hypogonadism (CHH) is classified as Kallmann syndrome (KS) with anosmia/hyposmia or normosmic (n)CHH. Here, we investigated the genetic causes and phenotype-genotype correlations in Japanese patients with CHH. Methods: We enrolled 22 Japanese patients with CHH from 21 families (18 patients with KS and 4 with nCHH) and analyzed 27 genes implicated in CHH by next-generation and Sanger sequencing. Results: We detected 12 potentially pathogenic mutations in 11 families, with three having a mutation in ANOS1 (X-linked recessive); three and four having a mutation in FGFR1 and CHD7, respectively (autosomal dominant); and one having two TACR3 mutations (autosomal recessive). Among four patients with KS carrying a CHD7 mutation, one had perceptive deafness and two had a cleft lip/palate. Conclusions: The frequency of CHH genes in the Japanese was compatible with previous reports, except that CHD7 mutations might be more common. Furthermore, partial phenotype-genotype correlations were demonstrated in our cohort.