Risks of ACTH therapy for West syndrome following BCG vaccination.

OBJECTIVE: Bacille de Calmette et Guérin (BCG) is a live vaccine for tuberculosis that is administered to all infants in Japan. Adrenocorticotropic hormone (ACTH) therapy for West syndrome (WS) causes immunosuppression and may result in BCG infection after BCG vaccination. We evaluated the safety of ACTH therapy initiated shortly after BCG vaccination. METHODS: We analyzed patients with WS who received ACTH therapy between 2005 and 2018. We evaluated the interval between BCG and ACTH therapy, and the rate of BCG infection during and after ACTH therapy, by retrospective chart review. RESULTS: Seventy-nine patients were included in the analysis. Twenty-three patients received ACTH therapy prior to BCG vaccination. For the remaining 56 patients, the median interval between BCG vaccination and the start of ACTH therapy (BCG-ACTH interval) was 91.5 (range 14-280) days. The BCG-ACTH interval was shorter in patients with unknown than in those with known etiologies. It was <8 weeks in 13 patients (10 with unknown and 3 with known etiologies). The minimum BCG-ACTH interval was 14 days. Six patients with epileptic spasms received BCG vaccinations because physicians did not recognize their seizures. None of the patients developed BCG infection. CONCLUSION: No patients who received ACTH therapy after BCG, even at an interval of 8 weeks, developed BCG infection. The timing of ACTH therapy initiation should be based on the risk of BCG-related adverse events and the adverse effects of any delay.

Peripheral nerves are involved in hypomyelinating leukodystrophy-3 caused by a homozygous AIMP1 variant.

INTRODUCTION: Aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1) is a non-catalytic component of the multi-tRNA synthetase complex that catalyzes the ligation of amino acids to their correct tRNAs. Bi-allelic truncating variants in the AIMP1 gene have been associated with hypomyelinating leukodystrophy-3 (HLD3; MIM 260600), which is characterized by hypomyelination, microcephaly, seizures and decreased life expectancy. Although peripheral nerve involvement has been assumed for HLD3, no compelling evidence is available to date. CASE REPORT: The case was a first-born Filipino male. He showed profound developmental delay, failure to thrive, and spasticity in his limbs. At three months of age he developed refractory epilepsy. Serial magnetic resonance imaging (MRIs) showed profound myelination delay and progressive cerebral atrophy. He showed abnormal nerve conduction studies. Genetic testing revealed a homozygous pathogenic variant in the AIMP1 gene (NM_004757.3: c.115C > T: p.Gln39*). The parents were heterozygous for the same variant. CONCLUSION: Here, we report a patient with a homozygous nonsense AIMP1 variant showing peripheral neuropathy as well as HLD3. Our case suggests that AIMP1 plays a pivotal role in the peripheral nerve as well as the central nervous system.

Frequent epileptic apnoea in a patient with Pitt-Hopkins syndrome.

Pitt-Hopkins syndrome is a rare genetic disease, characterised by severe intellectual disability, distinctive dysmorphic features, epilepsy and distinctive breathing abnormalities during wakefulness. Here, we describe the case of a 22-year-old woman with Pitt-Hopkins syndrome who presented with intractable generalised tonic seizures from the age of 11 years, which increased in frequency with age and onset of menstruation despite usage of some anticonvulsant drugs. From the age of 16 years, polysomnography and video-EEG led to the detection of frequent epileptic apnoea during sleep. Although the frequency of generalised tonic seizure clusters was reduced by treatment with phenobarbital and potassium bromide, epileptic apnoea persisted. Furthermore, frequent epileptic apnoea observed in our patient was regarded as a factor for aspiration and deterioration of respiratory function. This study indicates that patients with Pitt-Hopkins syndrome require close monitoring for epileptic apnoea. Moreover, long-term EEG and respiratory monitoring are necessary to distinguish epileptic apnoea from other respiratory disorders in patients with Pitt-Hopkins syndrome.

De novo 2q36.3q37.1 deletion encompassing TRIP12 and NPPC yields distinct phenotypes.

We report a patient with developmental delay, extremely short stature, small hands, dysmorphic facial features, hearing loss, and epilepsy carrying a de novo 2.76-Mb deletion of 2q36.3q37.1, including TRIP12 and NPPC. TRIP12 haploinsufficiency causes developmental delay with isolated dysmorphic facial features, whereas NPPC haploinsufficiency causes short stature and small hands. This is the first report of a unique phenotype, which is secondary to a microdeletion encompassing TRIP12 and NPPC.

Schaaf-Yang syndrome shows a Prader-Willi syndrome-like phenotype during infancy.

BACKGROUND: Schaaf-Yang syndrome (SYS) is a newly recognized imprinting related syndrome, which is caused by a truncating variant in maternally imprinted MAGEL2 located in 15q11-q13. Yet, precise pathomechanism remains to be solved. We sequenced MAGEL2 in patients suspected Prader-Willi syndrome (PWS) to delineate clinical presentation of SYS. We examined 105 patients with clinically suspected PWS but without a specific PWS genetic alteration. Sanger sequencing of the entire MAGEL2 gene and methylation-specific restriction enzyme treatment to detect the parent of origin were performed. Clinical presentation was retrospectively assessed in detail. RESULTS: Truncating variants in MAGEL2 were detected in six patients (5.7%), including a pair of siblings. All truncating variants in affected patients were on the paternally derived chromosome, while the healthy father of the affected siblings inherited the variant from his mother. Patients with MAGEL2 variants shared several features with PWS, such as neonatal hypotonia, poor suck, and obesity; however, there were also unique features, including arthrogryposis and a failure to acquire meaningful words. Additionally, an episode of neurological deterioration following febrile illness was confirmed in four of the six patients, which caused severe neurological sequalae. CONCLUSIONS: SYS can be present in infants suspected with PWS but some unique features, such as arthrogryposis, can help discriminate between the two syndromes. An episode of neurological deterioration following febrile illness should be recognized as an important complication.

A novel CUL4B splice site variant in a young male exhibiting less pronounced features.

Patients with variants in CUL4B exhibit syndromic intellectual disability (MIM #300354). A seven-year-old boy presented with intellectual disability, a history of seizure, characteristic facial features, and short stature. Whole-exome sequencing detected a c.974+3A>G variant in CUL4B, which was subsequently confirmed to disrupt mRNA splicing. The current patient showed less pronounced phenotypic features compared with the previously reported cases. This report, therefore, provides evidence of genotype-phenotype correlations in CUL4B-related disorders.

De novo variants in SETD1B cause intellectual disability, autism spectrum disorder, and epilepsy with myoclonic absences.

Epilepsy with myoclonic absences is a specific seizure type characterized by bilateral rhythmic clonic jerks with impairment of consciousness. Here, we report an individual with epilepsy with myoclonic absences, mild intellectual disabilities, language disorder, and autism spectrum disorder. His interictal electroencephalogram revealed a spike-and-slow wave complex dominant in the frontal area. His ictal polygraphic and video-electroencephalogram showed a characteristic diffuse synchronous 3-Hz spike-and-wave burst associated with bilateral upper limb myoclonic jerks with impairment of consciousness. Using whole-exome sequencing, we found a novel de novo variant, c.386T>G, p.(Val129Gly), in SETD1B (SET domain containing 1B). We previously reported that two individuals with a de novo SETD1B variant showed intellectual disability, epilepsy, and autism. Of note, one of those individuals and the present case showed epilepsy with myoclonic absences. Therefore, this report supports the indication that SETD1B may be a causative gene for neurodevelopmental disorders and suggests that epilepsy with myoclonic absences may be a characteristic feature of SETD1B-related disorders.

Delayed recognition of childhood arterial ischemic stroke.

BACKGROUND: Few population-based surveys of childhood arterial ischemic stroke (AIS) have been conducted in Asian countries. The aim of this study was to investigate the clinical features, time to diagnosis, and prognosis of childhood AIS in a population-based cohort in Japan. METHODS: Children aged 29 days-15 years 11 months old, residing in the Aichi Prefecture of Japan with radiologically confirmed AIS during 2010-2014, were identified retrospectively through questionnaires. We analyzed 40 children (23 boys, 17 girls; median age, 7 years 3 months), and collected time interval information of 26 patients. The time from clinical onset to first physician assessment and the time to AIS diagnosis were calculated. RESULTS: The most common presentation was paralysis or paresis in 27 patients (71%). No underlying disorders or possible trigger factors were identified in 14 patients (35%). The median time from symptom onset to first physician assessment was 2.9 h. The median time from symptom onset to the confirmed AIS diagnosis was 27.0 h. The diagnosis of AIS was made in the first 6 h after onset of symptoms in 27% of patients for whom the time was available. Radiological diagnosis took longer than 24 h in 54% of these patients. CONCLUSIONS: Long in-hospital delays exist in the diagnosis of AIS in children, likely due to lack of awareness of stroke by doctors. Further efforts to increase public and physician awareness of childhood stroke are needed to ensure early diagnosis and treatment.

Transition from Leigh syndrome to MELAS syndrome in a patient with heteroplasmic MT-ND3 m.10158T>C.

An m.10158T>C mutation in MT-ND3, encoding a subunit of respiratory complex I, causes early-onset Leigh syndrome (LS), mitochondrial encephalomyopathy with lactic acid and stroke-like episodes (MELAS) syndrome, and LS and MELAS overlapping syndrome, presumably dependent on the ratio of heteroplasmy. Herein, we report a 4-year-old girl with heteroplasmic m.10158T>C mutation, showing an evolving age-dependent phenotype from LS to MELAS syndromes. She showed mild developmental delay during infancy, which was associated with magnetic resonance imaging lesions in the brain stem and basal ganglia. At the age of 4 years, she developed rapid neurological deterioration and intractable seizures, which was associated with recurrent multiple cerebral lesions as well as basal ganglia lesions. Her cerebral lesions were located predominantly in white matter and appeared at multiple areas simultaneously, unique characteristics that are distinct from typical MELAS. Two patients with LS-MELAS overlapping syndrome with m.10158T>C have been previously reported, however, this is the first patient with m.10158T>C showing significant age-dependent changes in clinical features and neuro-images, implying an age-dependent role of complex I in the developing brain.

A novel splicing mutation in SLC9A6 in a boy with Christianson syndrome.

A loss of function mutation in SLC9A6 (Xq26.3) is responsible for Christianson syndrome in males. We identified a novel splicing mutation (NM_006359.2:c.1141-8C>A) of SLC9A6 in a seven-year-old boy with microcephaly, severe developmental delay, and intractable epilepsy. Functional analysis found multiple aberrant transcripts, none of which maintained the canonical open reading frame. Computer prediction tools, however, failed to detect all of the aberrant transcripts.

Author Correction: A missense mutation in the HECT domain of NEDD4L identified in a girl with periventricular nodular heterotopia, polymicrogyria, and cleft palate.

Since the publication of this article, it has been brought to our attention, that the identified mutation (NM_015277: c.2617 G > A; p.Glu873Lys) is identical with the mutation (NM_001144967: c.2677 G > A; p.Glu893Lys) reported by Broix et al (Nature Genetics 48, 1349-1358, 2016 https://doi.org/10.1038/ng.3676 ). Therefore the mutation is not novel but recurrent. Accordingly, the word "novel" should be deleted throughout the article including the title. Thus, the title should read "A missense mutation in the HECT domain of NEDD4L identified in a girl with periventricular nodular heterotopia, polymicrogyria, and cleft palate."

A case of early-onset epileptic encephalopathy with a homozygous TBC1D24 variant caused by uniparental isodisomy.

TBC1D24-related disorders are rare neurodevelopmental disorders that show a broad range of neuropsychiatric deficits and are mostly inherited in an autosomal recessive manner. Here we describe a case with early-onset epileptic encephalopathy, in whom exome sequencing detected a novel pathogenic homozygous c.442G>A, p.(Glu148Lys) variant in TBC1D24. She showed severe developmental delay, congenital sensorineural hearing loss and seizures, but the combination of a high dose phenobarbital and potassium bromide was very effective for the seizures. Sanger sequencing revealed that her mother was a heterozygous carrier of the TBC1D24 variant, but her father showed only wild-type alleles. Homozygosity mapping analysis using exome data showed loss of the heterozygosity region at 16p13.3-p13.13 encompassing TBC1D24. Genotyping analysis using rare variants within loss of the heterozygosity region indicated that the patient has a homozygous haplotype inherited from her mother, indicating maternal segmental uniparental isodisomy (UPiD). These data clearly show that exome sequencing is a powerful tool to perform comprehensive genetic analysis.

MYCN de novo gain-of-function mutation in a patient with a novel megalencephaly syndrome.

BACKGROUND: In this study, we aimed to identify the gene abnormality responsible for pathogenicity in an individual with an undiagnosed neurodevelopmental disorder with megalencephaly, ventriculomegaly, hypoplastic corpus callosum, intellectual disability, polydactyly and neuroblastoma. We then explored the underlying molecular mechanism. METHODS: Trio-based, whole-exome sequencing was performed to identify disease-causing gene mutation. Biochemical and cell biological analyses were carried out to elucidate the pathophysiological significance of the identified gene mutation. RESULTS: We identified a heterozygous missense mutation (c.173C>T; p.Thr58Met) in the MYCN gene, at the Thr58 phosphorylation site essential for ubiquitination and subsequent MYCN degradation. The mutant MYCN (MYCN-T58M) was non-phosphorylatable at Thr58 and subsequently accumulated in cells and appeared to induce CCND1 and CCND2 expression in neuronal progenitor and stem cells in vitro. Overexpression of Mycn mimicking the p.Thr58Met mutation also promoted neuronal cell proliferation, and affected neuronal cell migration during corticogenesis in mouse embryos. CONCLUSIONS: We identified a de novo c.173C>T mutation in MYCN which leads to stabilisation and accumulation of the MYCN protein, leading to prolonged CCND1 and CCND2 expression. This may promote neurogenesis in the developing cerebral cortex, leading to megalencephaly. While loss-of-function mutations in MYCN are known to cause Feingold syndrome, this is the first report of a germline gain-of-function mutation in MYCN identified in a patient with a novel megalencephaly syndrome similar to, but distinct from, CCND2-related megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome. The data obtained here provide new insight into the critical role of MYCN in brain development, as well as the consequences of MYCN defects.

A novel homozygous missense mutation in the SH3-binding motif of STAMBP causing microcephaly-capillary malformation syndrome.

Microcephaly-capillary malformation syndrome is a congenital and neurodevelopmental disorder caused by biallelic mutations in the STAMBP gene. Here we identify the novel homozygous mutation located in the SH3 binding motif of STAMBP (NM_006463.4) (c.707C>T: p.Ser236Phe) through whole-exome sequencing. The case patient was a 2-year-old boy showing severe global developmental delay, progressive microcephaly, refractory seizures, dysmorphic facial features, and multiple capillary malformations. Immunoblot analysis of patient-derived lymphoblastoid cell lines (LCLs) revealed a severe reduction in STAMBP expression, indicating that Ser236Phe induces protein instability. STAMBP interacts with the SH3 domain of STAM and transduces downstream signals from the Jaks-STAM complex. The substitution of Ser236Phe found in the case patient was located in the SH3-binding motif, and we propose the mutation may block STAM binding and subsequently induce STAMBP degradation. Contrary to previously reported STAMBP mutations, the Ser236Phe mutation did not lead to constitutive activation of the PI3K-AKT-mTOR pathway in patient-derived LCLs, as indicated by the expression of phosphorylated S6 ribosomal protein, suggesting that it is not the major pathomechanism underlying the disorder in this patient.

Distinctive facies, macrocephaly, and developmental delay are signs of a PTEN mutation in childhood.

BACKGROUND: Germline mutations of the PTEN gene are responsible for several PTEN hamartoma tumor syndromes. They are also implicated as a cause of macrocephaly and mild to severe developmental delay, regardless of the presence or absence of hamartomas in childhood. Nevertheless, because of limited information, the clinical features present during childhood in patients with a PTEN mutation are yet to be elucidated. METHODS: PTEN mutations were investigated by multiplex targeted sequencing of genomic DNA from 33 children with increased head circumference (>+2 SD) and developmental delay. The clinical features of all the patients with a PTEN mutation were abstracted by dysmorphologists. RESULTS: We have identified six children with a PTEN mutation. Clinical dissection of these six patients, in addition to patient reports in the literature, revealed distinctive facial features that included frontal bossing, dolichocephaly, horizontal eyebrows, and a depressed nasal bridge. Macrocephaly (+3.2 to +6.0 SD) was noticeable compared to their height (-0.8 to +2.1 SD), and the difference in the SD value of head circumference and height was more than 3 SD in all patients. CONCLUSION: The presence of distinctive facies, extreme macrocephaly with normal to mildly high stature, and developmental delay may be useful for identifying patients with a PTEN mutation in childhood. Early identification of patients with a PTEN mutation would help uncover the natural course of tumor development in this group of individuals who have a possible predisposition to cancer, and be important for the development of an optimal surveillance strategy.

A novel truncating mutation in FLNA causes periventricular nodular heterotopia, Ehlers-Danlos-like collagenopathy and macrothrombocytopenia.

INTRODUCTION: Filamin A (FLNA) is located in Xq28, and encodes the actin binding protein, filamin A. A mutation in FLNA is the most common cause of periventricular nodular heterotopia (PVNH), but a clear phenotype-genotype correlation has not been established. Indeed, some patients with a FLNA mutation have recently been shown to additionally have Ehlers-Danlos-like collagenopathy or macrothrombocytopenia. In an attempt to establish a clearer correlation between clinical symptoms and genotype, we have investigated a phenotype that involves thrombocytopenia in a patient with a truncation of the FLNA gene. CASE REPORT: We present the case of a 4-year-old girl who, at birth, showed a ventral hernia. At 2 months of age, she was diagnosed with patent ductus arteriosus (PDA) and aortic valve regurgitation. At 11 months, she underwent ligation of the PDA. She was also diagnosed with diaphragmatic eventration by a preoperative test. At 19 months, motor developmental delay was noted, and brain MRI revealed bilateral PVNH with mega cisterna magna. Presently, there is no evidence of epilepsy, intellectual disability or motor developmental delay. She has chronic, mild thrombocytopenia, and a platelet count that transiently decreases after viral infection. Dilation of the ascending aorta is progressing gradually. Genetic testing revealed a de novo nonsense heterozygous mutation in FLNA (NM_001456.3: c.1621G > T; p.Glu541Ter). Immunofluorescence staining of a peripheral blood smear showed a lack of filamin A expression in 21.1% of her platelets. These filamin A-negative platelets were slightly larger than her normal platelets. CONCLUSION: Our data suggests immunofluorescence staining of peripheral blood smears is a convenient diagnostic approach to identify patients with a FLNA mutation, which will facilitate further investigation of the correlation between FLNA mutations and patient phenotype.

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.

A de novo p.Arg756Cys mutation in ATP1A3 causes a distinct phenotype with prolonged weakness and encephalopathy triggered by fever.

Patients with a mutation at Arg756 in ATP1A3 have been known to exhibit a distinct phenotype, characterized by prolonged weakness and encephalopathy, triggered by febrile illness. With only eight reports published to date, more evidence is required to correlate clinical features with a mutation at Arg756. Here we report an additional case with an Arg756Cys mutation in ATP1A3. A four-year-old boy showed mild developmental delay with recurrent paroxysmal episodes of weakness and encephalopathy from nine months of age. Motor deficits, which included bilateral hypotonia, ataxia, dysmetria, limb incoordination, dysarthria, choreoathetosis, and dystonia, were observed from one year and three months. Whole-exome sequencing detected a heterozygous de novo variant at c.2266C>T (p.Arg756Cys) in ATP1A3. The episodic course and clinical features of this case were consistent with previously reported cases with mutations at Arg756. Furthermore, his phenotype of marked ataxia was more similar to that of an Arg756Cys patient with relapsing encephalopathy and cerebellar ataxia syndrome, than to those with Arg756His and Arg756Leu mutations. This report therefore provides evidence of genotype-phenotype correlations in ATP1A3-related disorders as well as in patients with mutations at Arg756 in ATP1A3.

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

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.

CTCF deletion syndrome: clinical features and epigenetic delineation.

BACKGROUND: Heterozygous mutations in CTCF have been reported in patients with distinct clinical features including intellectual disability. However, the precise pathomechanism underlying the phenotype remains to be uncovered, partly because of the diverse function of CTCF. Here we describe extensive clinical and genetic investigation for two patients with a microdeletion encompassing CTCF. METHODS: We performed genetic examination including comprehensive investigation of X chromosome inactivation and DNA methylation profiling at imprinted loci and genome-wide. RESULTS: Two patients showed comparable clinical features to those in a previous report, indicating that haploinsufficiency of CTCF was the major determinant of the microdeletion syndrome. Despite the haploinsufficiency of CTCF, X chromosome inactivation was normal. DNA methylation at imprinted loci was normal, but hypermethylation at CTCF binding sites was demonstrated, of which PRKCZ and FGFR2 were identified as candidate genes. CONCLUSIONS: This study confirms that haploinsufficiency of CTCF causes distinct clinical features, and that a microdeletion encompassing CTCF could cause a recognisable CTCF deletion syndrome. Perturbed DNA methylation at CTCF binding sites, not at imprinted loci, may underlie the pathomechanism of the syndrome.