Leucine-485 deletion variant of BRAF may exhibit the severe end of the clinical spectrum of CFC syndrome.

The genotype-phenotype correlation in BRAF variant in cardio-facio-cutaneous (CFC) syndrome is not clearly defined. Here we report a case with a severe clinical phenotype and a novel BRAF variant, p.Leu485del. The present case showed severe intellectual disability, impaired awareness, hyperekplexia, involuntary movements, early onset refractory seizures, and delayed myelination on brain magnetic resonance imaging as well as a polycystic and dysplastic kidney, which are previously unreported anomalies in CFC or RAS/mitogen-activated protein kinase syndromes related to BRAF variant. CFC syndrome, especially caused by BRAF variant, should be included in the differential diagnosis of patients with developmental and epileptic encephalopathies and hyperekplexia. Furthermore, we need to keep in mind that missense variants or the deletion of Leucine-485 may be associated with severe symptoms.

Prolonged mild disturbance of consciousness and acute encephalopathy.

BACKGROUND: Acute encephalopathy (AE) is defined by the Japanese guidelines as the acute disturbance of consciousness (Glasgow coma scale [GCS] score ≤11) that persists for >24 h. We have often encountered, however, cases of prolonged mild disturbance of consciousness (PMDC) with GCS score >11, meaning that they do not fit the guideline definition of AE. The reports of these cases have been relatively sparse, and the nosological position, prognosis, and other characteristics remain unknown. To clarify the characteristics of PMDC we compared cases of PMDC with cases of AE. METHODS: This study was a retrospective observational study at a tertiary children's hospital in Japan. We studied children with a diagnosis of AE or PMDC between January 2011 and August 2016. RESULTS: Thirteen cases of PMDC and 19 cases of AE were identified during the study period. PMDC patients more frequently had hyponatremia (P < 0.01), paradoxical arousal response on electroencephalogram (P = 0.010), normal computed tomography (CT; P = 0.025), and normal magnetic resonance imaging (MRI; P < 0.01) than the AE patients. Sequelae were more frequently observed in AE than in PMDC patients (P = 0.011). CONCLUSIONS: PMDC has different characteristics to AE with regard to hyponatremia, paradoxical arousal response, CT or MRI findings, and prognosis. Despite the differences, PMDC might also be regarded as being a milder member of the wide variety of AE and related diseases.

Genomic analysis identifies masqueraders of full-term cerebral palsy.

OBJECTIVE: Cerebral palsy is a common, heterogeneous neurodevelopmental disorder that causes movement and postural disabilities. Recent studies have suggested genetic diseases can be misdiagnosed as cerebral palsy. We hypothesized that two simple criteria, that is, full-term births and nonspecific brain MRI findings, are keys to extracting masqueraders among cerebral palsy cases due to the following: (1) preterm infants are susceptible to multiple environmental factors and therefore demonstrate an increased risk of cerebral palsy and (2) brain MRI assessment is essential for excluding environmental causes and other particular disorders. METHODS: A total of 107 patients-all full-term births-without specific findings on brain MRI were identified among 897 patients diagnosed with cerebral palsy who were followed at our center. DNA samples were available for 17 of the 107 cases for trio whole-exome sequencing and array comparative genomic hybridization. We prioritized variants in genes known to be relevant in neurodevelopmental diseases and evaluated their pathogenicity according to the American College of Medical Genetics guidelines. RESULTS: Pathogenic/likely pathogenic candidate variants were identified in 9 of 17 cases (52.9%) within eight genes: CTNNB1,CYP2U1,SPAST,GNAO1,CACNA1A,AMPD2,STXBP1, and SCN2A. Five identified variants had previously been reported. No pathogenic copy number variations were identified. The AMPD2 missense variant and the splice-site variants in CTNNB1 and AMPD2 were validated by in vitro functional experiments. INTERPRETATION: The high rate of detecting causative genetic variants (52.9%) suggests that patients diagnosed with cerebral palsy in full-term births without specific MRI findings may include genetic diseases masquerading as cerebral palsy.

A patient with Muenke syndrome manifesting migrating neonatal seizures.

We report a patient with Muenke syndrome who had repetitive apneic spell followed by focal status epilepticus in the early infancy. Ictal EEG showed focal spikes bursts originated from the left hemisphere and sifted to the right hemisphere, during which he had migrating tonic seizures from right side of the body to the left side of the body. Brain MRI showed abnormal development of bilateral hippocampus, which was characterized as abnormal folding of hippocampal gyri. However, the long-term seizure prognosis was favorable. Results from this and previous studies failed to support the notion that FGFR3 (P250) mutation results in epileptic encephalopathy.

A novel mutation in the proteolytic domain of LONP1 causes atypical CODAS syndrome.

Cerebral, ocular, dental, auricular, skeletal (CODAS) syndrome is a rare autosomal recessive multisystem disorder caused by mutations in LONP1. It is characterized by intellectual disability, cataracts, delayed tooth eruption, malformed auricles and skeletal abnormalities. We performed whole-exome sequencing on a 12-year-old Japanese male with severe intellectual disability, congenital bilateral cataracts, spasticity, hypotonia with motor regression and progressive cerebellar atrophy with hyperintensity of the cerebellar cortex on T2-weighted images. We detected compound heterozygous mutation in LONP1. One allele contained a paternally inherited frameshift mutation (p.Ser100Glnfs*46). The other allele contained a maternally inherited missense mutation (p.Arg786Trp), which was predicted to be pathogenic by web-based prediction tools. The two mutations were not found in Exome Variant Server or our 575 in-house control exomes. Some features were not consistent with CODAS syndrome but overlapped with Marinesco-Sjögren syndrome, a multisystem disorder caused by a mutation in SIL1. An atypical mutation site may result in atypical presentation of the LONP1 mutation.

Patchy white matter hyperintensity in ring chromosome 18 syndrome.

Ring chromosome 18 syndrome is a chromosomal abnormality in which partial deletions occur at both ends of chromosome 18, that is, distally on the short and long arms. Previously reported brain magnetic resonance imaging (MRI) abnormalities include diffuse hyperintensity in the white matter, which has been regarded as hypomyelination because the gene for myelin basic protein production is located on the long arm of chromosome 18. We report the case of a 14-year-old boy with ring chromosome 18 syndrome, whose MRI showed patchy asymmetrical T2 and fluid-attenuated inversion-recovery hyperintensities in the deep white matter as well as diffuse hypomyelination. These patchy lesions may indicate demyelination or gliosis rather than hypomyelination. This result differs from previous reports.

First Japanese variant of late infantile neuronal ceroid lipofuscinosis caused by novel CLN6 mutations.

The clinical phenotypes of neuronal ceroid lipofuscinoses (NCLs) have been determined based on the age of onset and clinical symptoms. NCLs with onset between age 2 and 4years are known as late infantile neuronal ceroid lipofuscinoses (LINCLs). The clinical features of LINCLs include visual loss and progressive myoclonus epilepsy (PME) characterized by myoclonus, seizures, ataxia, and both mental and motor deterioration. There have been reports of several genes associated with LINCLs, with mutations in the CLN6 gene reported to cause variant forms of LINCLs (vLINCLs). Here, we report the first Japanese vLINCL caused by novel CLN6 mutations, found in a patient diagnosed by whole-exome sequencing. Visual acuity in our patient was preserved until the early teens. It remains to be elucidated if preserved visual function is related to the novel mutations of CLN6. Our case reveals the efficacy of whole-exome sequencing for examination of PMEs and highlights the existence of the CLN6 mutation in the Japanese population.

FDG-PET study of patients with Leigh syndrome.

We conducted a [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) study in five patients (median age 11 (range 4-13) years) with Leigh syndrome to evaluate its usefulness for understanding the functional brain dysfunction in this disease and in future drug trials. Four patients were found to have reported mitochondrial DNA gene mutations. The brain T2-weighted magnetic resonance imaging (MRI) showed high-intensity areas in the putamen bilaterally in five patients, caudate bilaterally in four, thalamus bilaterally in two, and brainstem in one. Cerebellar atrophy was observed in older two patients. For disease control, seven age-matched epilepsy patients who had normal MRI and FDG-PET studies were selected. For semiquantitative analysis of the lesions with decreased (18)F-FDG uptake, the mean standard uptake value (SUV) was calculated in regions of interest (ROIs) placed in each brain structure. We compared the SUV of nine segments (the frontal, temporal, parietal, and occipital lobes, thalami, basal ganglia, mid-brain, pons, and cerebellum) between patients with Leigh syndrome and controls. The glucose uptake was decreased significantly in the cerebellum and basal ganglia, which could explain the ataxia and dystonia in patients with Leigh syndrome. Although this study had some limitations, FDG-PET might be useful for evaluating the brain dysfunction and treatment efficacy of new drugs in patients with Leigh syndrome. Further study with more patients using advanced methods to quantify glucose uptake is needed before drawing a conclusion.

Outcome of hemiplegic cerebral palsy born at term depends on its etiology.

OBJECTIVES: To elucidate the etiology and its relationship to the outcomes of hemiplegic cerebral palsy (HCP). PARTICIPANTS AND METHODS: MR images and outcomes of 156 children with HCP born at term and older than three years were investigated in two major centers for cerebral palsy in Japan. Etiologies were classified into perinatal ischemic stroke (PIS), cerebral dysgenesis (CD), and others. PIS was divided into periventricular venous infarction (PVI) and two types of arterial infarction; middle cerebral artery infarction (MCAI) and deep gray matter infarction (DGMI). Initial signs and the time of presentation were investigated among the three types of PIS. As functional outcomes, laterality of paresis, age at initial walk, affected hand's function, intellectual development, and occurrence of epilepsy were compared among all the four types. ETIOLOGY: PIS was found in 106 children (68%), while CD accounted for 28 (18%). Among PIS, venous infarction was more common than arterial infarction (62:44). OUTCOMES: PVI revealed later presentation of motor asymmetry and more involvement of lower extremity as the initial sign among PIS groups. Only MCAI showed right-side predominance in laterality of paresis. DGMI related to better intellectual development and PVI showed lower occurrence of epilepsy, while there was no significant difference in affected hand's function among the four groups. PIS groups showed significantly earlier attainment of independent walk, better intellectual development, and lower occurrence of epilepsy than CD. CONCLUSIONS: PVI was the most common cause of HCP born at term, and the etiology closely related to the initial signs of hemiplegia and overall outcomes.