Diagnostic value of whole-exome sequencing in Chinese pediatric-onset neuromuscular patients.

BACKGROUND: Neuromuscular disorders (NMDs) comprise a group of heterogeneous genetic diseases with a broad spectrum of overlapping the clinical presentations that makes diagnosis challenging. Notably, the recent introduction of whole-exome sequencing (WES) is introducing rapid changes on the genetic diagnosis of NMDs. We aimed to investigate the diagnostic value of WES for pediatric-onset NMDs. METHODS: We applied integrated diagnostic approach and performed WES in 50 Chinese subjects (30 males, 20 females) with undiagnosed pediatric-onset NMDs despite previous specific tests. The patients were categorized in four subgroups according to phenotyping and investigation findings. Variants on NMDs gene list and open exome analysis for those with initial negative findings were identified. RESULTS: WES identified causative variants in ACTA1 (n = 2), POMT1, COL6A1 (n = 2), MTMR2, LMNA, SELENON, DNM2, TGFB1, MPZ, IGHMBP2, and LAMA2 in 13 patients. Two subjects have variants of uncertain significance (VUSs) in TTN and SCN11A, unlikely to be pathogenic due to incompatible phenotypes. The mean interval time from symptom onset to genetic diagnosis was 10.4 years (range from 1 month to 33 years). The overall diagnostic yield of WES in our cohort was 26%. Open exome analysis was necessary to identify the pathogenic variant in TGFB1 that caused skeletal dysplasia with neuromuscular presentation. CONCLUSION: Our study shows a clear role of WES in the pathway of integrated diagnostic approach to shorten the diagnostic odyssey in patients with rare NMDs.

Oral health status of children with epilepsy in Hong Kong.

AIM: This study assessed and compared the oral health status, dental trauma experience and oral health habits of children with and without epilepsy. METHODS: Thirty-five children with epilepsy aged 3-18 years old were recruited from the pediatric neurology clinics of 2 university-affiliated district hospitals. A sample of 35 age- and gender-matched healthy children was recruited as controls. Clinical data on caries, gingival health, oral hygiene level and dental trauma were collected and compared between the groups. Information about children's oral health habits and reported dental trauma experience were obtained by structured questionnaire. RESULTS: Children with epilepsy had significantly poorer gingival health than healthy controls. No significant differences in dental caries experience, oral hygiene level, dental trauma experience, oral health habits and dental care service utilization were observed between the children with and without epilepsy. Among the children with epilepsy, those taking more than 1 antiepileptic drug had a greater prevalence of dental caries when compared with those receiving mono-antiepileptic drug therapy. The presence of gingival hyperplasia indicated poorer gingival health in epileptic children. CONCLUSION: The study shows that children with epilepsy had poorer oral health status in terms of gingival health than those without epilepsy.

International Paediatric Mitochondrial Disease Scale.

OBJECTIVE: There is an urgent need for reliable and universally applicable outcome measures for children with mitochondrial diseases. In this study, we aimed to adapt the currently available Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) to the International Paediatric Mitochondrial Disease Scale (IPMDS) during a Delphi-based process with input from international collaborators, patients and caretakers, as well as a pilot reliability study in eight patients. Subsequently, we aimed to test the feasibility, construct validity and reliability of the IPMDS in a multicentre study. METHODS: A clinically, biochemically and genetically heterogeneous group of 17 patients (age 1.6-16 years) from five different expert centres from four different continents were evaluated in this study. RESULTS: The feasibility of the IPMDS was good, as indicated by a low number of missing items (4 %) and the positive evaluation of patients, parents and users. Principal component analysis of our small sample identified three factors, which explained 57.9 % of the variance. Good construct validity was found using hypothesis testing. The overall interrater reliability was good [median intraclass correlation coefficient for agreement between raters (ICCagreement) 0.85; range 0.23-0.99). CONCLUSION: In conclusion, we suggest using the IPMDS for assessing natural history in children with mitochondrial diseases. These data should be used to further explore construct validity of the IPMDS and to set age limits. In parallel, responsiveness and the minimal clinically important difference should be studied to facilitate sample size calculations in future clinical trials.

Autism Developmental Profiles and Cooperation with Oral Health Screening.

To determine the associations between autism developmental profiles and cooperation with an oral health screening among preschool children with autism spectrum disorders (ASDs). A random sample of Special Child Care Centres registered with the Government Social Welfare Department in Hong Kong was selected (19 out of 37 Centres). All preschool children with ASDs were invited to participate in the oral health survey and 347 children agreed to participate (among 515 invited). A checklist of autism developmental profiles: (1) level of cognitive functioning, (2) social skills development, (3) communication skills development, (4) reading skills and (5) challenging behaviours was ascertained. Feasibility of conducting oral health screening in preschool children with ASDs was associated with their cognitive functioning (p = 0.001), social skills development (p = 0.002), communication skills development (p < 0.001), reading skills (p < 0.001) and challenging behaviours (p = 0.06). In regression analyses accounting for age (in months) and gender, inability to cooperate with an oral health screening was associated with high level of challenging behaviours (OR 10.50, 95 % CI 2.89-38.08, p < 0.001) and reduced cognitive functioning (OR 5.29, 95 % CI 1.14-24.61, p = 0.034). Age (in months) was positively associated with likelihood of cooperative behaviour with an oral health screening (OR 1.06, 95 % CI 1.03, 1.08, p < 0.001). Feasibility of conducting population-wide oral health screening among preschool children with ASDs is associated with their developmental profiles; and in particular levels of cognitive functioning, and challenging behaviours.

Ability and Disability in Autism Spectrum Disorder: A Systematic Literature Review Employing the International Classification of Functioning, Disability and Health-Children and Youth Version.

OBJECTIVE: This study is the first in a series of four empirical investigations to develop International Classification of Functioning, Disability and Health (ICF) Core Sets for Autism Spectrum Disorder (ASD). The objective was to use a systematic review approach to identify, number, and link functional ability and disability concepts used in the scientific ASD literature to the nomenclature of the ICF-CY (Children and Youth version of the ICF, covering the life span). METHODS: Systematic searches on outcome studies of ASD were carried out in Medline/PubMed, PsycINFO, ERIC and Cinahl, and relevant functional ability and disability concepts extracted from the included studies. These concepts were then linked to the ICF-CY by two independent researchers using a standardized linking procedure. New concepts were extracted from the studies until saturation of identified ICF-CY categories was reached. RESULTS: Seventy-one studies were included in the final analysis and 2475 meaningful concepts contained in these studies were linked to 146 ICF-CY categories. Of these, 99 categories were considered most relevant to ASD (i.e., identified in at least 5% of the studies), of which 63 were related to Activities and Participation, 28 were related to Body functions, and 8 were related to Environmental factors. The five most frequently identified categories were basic interpersonal interactions (51%), emotional functions (49%), complex interpersonal interactions (48%), attention functions (44%), and mental functions of language (44%). CONCLUSION: The broad variety of ICF-CY categories identified in this study reflects the heterogeneity of functional differences found in ASD--both with respect to disability and exceptionality--and underlines the potential value of the ICF-CY as a framework to capture an individual's functioning in all dimensions of life. The current results in combination with three additional preparatory studies (expert survey, focus groups, and clinical study) will provide the scientific basis for defining the ICF Core Sets for ASD for multipurpose use in basic and applied research and every day clinical practice of ASD.

ATP1A3 mutation in a Chinese girl with alternating hemiplegia of childhood--Potential target of treatment?

BACKGROUND: This Chinese girl had alternating hemiplegia of childhood (AHC) since 2 months. She failed to respond to anticonvulsants, antimigrainous drugs and calcium channel blockers but achieved complete remission steroid treatment for 4 weeks and relapsed after stopping steroid. PURPOSE: In order to clarify the unknown etiology, genetic analysis of ATP1A3 gene, which encodes the alpha3-subunit of the sodium/potassium-transporting ATPase (Na, K-ATPase), has been done by Sanger sequencing. RESULTS: A de novo heterozygous missense mutation (c.2401G>A; p.D801N) was identified in exon 17 of ATP1A3 gene and this is one of the hotspot mutations found in AHC patients. CONCLUSION: It will be interesting to further investigate whether Na, K-ATPase was the target of corticosteroid treatment.

Prevalence and Characteristics of Chinese Patients With Duchenne and Becker Muscular Dystrophy: A Territory Wide Collaborative Study in Hong Kong.

The aim of this collaborative study on Duchenne muscular dystrophy and Becker muscular dystrophy is to determine the prevalence and to develop data on such patients as a prelude to the development of registry in Hong Kong. Information on clinical and molecular findings, and patient care, was systematically collected in 2011 and 2012 from all Pediatric Neurology Units in Hong Kong. Ninety patients with dystrophinopathy were identified, and 83% has Duchenne muscular dystrophy. The overall prevalence of dystrophinopathy in Hong Kong in 2010 is 1.03 per 10 000 males aged 0 to 24 years. Among the Duchenne group, we observed a higher percentage (40.6%) of point mutations with a lower percentage (45.3%) of exon deletions in our patients when compared with overseas studies. Although we observed similar percentage of Duchenne group received scoliosis surgery, ventilation support, and cardiac treatment when compared with other countries, the percentage (25%) of steroid use is lower.

Spinal primitive neuroectodermal tumor mimicking as chronic inflammatory demyelination polyneuropathy: a case report and review of literature.

We report a young boy who presented with progressive weakness of lower extremities associated with areflexia and abnormal electrophysiological findings initially suggestive of chronic inflammatory demyelinating polyneuropathy. Initial lumbosacral spinal magnetic resonance imaging (MRI) showed thickened descending spinal nerve roots only. Immunomodulating therapy was given but with limited clinical response. Repeated spine magnetic resonance imaging showed cauda equina and also new spinal cord extramedullary contrast enhancement. The initial extensive investigations including open biopsy did not point to any specific diagnosis. Only through pursuing a repeated biopsy, the diagnosis of the spinal peripheral primitive neuroectodermal tumor was confirmed. This case highlights the diagnostic challenges of the spinal peripheral primitive neuroectodermal tumor that could have an initial chronic inflammatory demyelinating polyneuropathy-like presentation. The literature review confirms that this is a rare condition and cauda equina origin has only been reported in adults and teenagers, and this is the first reported case in a young child.

SCN2A mutation in a Chinese boy with infantile spasm - response to Modified Atkins Diet.

BACKGROUND: Mutation of SCN2A, encoding for voltage-gated sodium channel type II alpha subunit, has been demonstrated in various epilepsy phenotypes, ranging from benign to severe epileptic disorders and recently this had been reported for cases with infantile spasm (IS). METHODS: We study a 6 years-old Chinese boy with severe developmental delay who had infantile spasm since 15 months. He later had severe intellectual disability and autistic features. He failed to respond to most anticonvulsants. Modified Atkins Diet was introduced at 4 years of age and he showed a seizure remission for 12 months with only 1 anticonvulsants. To clarify the unknown etiology, mutations were screened for genes associated with brain development or synaptic function. RESULTS: A heterozygous mutation (c.3631G>A; p.E1211K) was identified in exon 21 of SCN2A gene. This mutation has been reported previously only in a Japanese patient with IS. CONCLUSION: This is the first case of SCN2A mutation identified in Chinese. Similarity of our case and one Japanese case of infantile spasm indicated that this E1211K mutation is important as possible etiology of IS. Trial of Modified Atkins Diet for other cases of infantile spasm with similar SCN2A mutations is worthwhile pursuing.

Diversity in the androgen receptor CAG repeat has been shaped by a multistep mutational mechanism.

The androgen receptor (AR) gene encodes a type of nuclear receptor that functions as a steroid-hormone activated transcription factor. In its coding region, AR includes a CAG repeat, which has been intensely studied due to the inverse correlation between repeat size and AR transcriptional activity. Several studies have reported different (CAG)n sizes associated with the risk of androgen-linked diseases. We aimed at clarifying the mechanisms on the origin of newly CAG sized alleles through a strategy involving the analysis of the associated haplotype diversity. We genotyped 374 control individuals of European and Asian ancestry, and reconstructed the haplotypes associated with the CAG repeat, defined by 10 SNPs and 6 flanking STRs. The most powerful SNPs to tag AR lineages are rs7061037-rs12012620 and rs34191540-rs6625187-rs2768578 in Europeans and Asians, respectively. In the most frequent AR lineage, (CAG)18 alleles seem to have been generated by a multistep mutation mechanism, most probably from longer alleles. We further noticed that the DXS1194-DXS1111 haplotype, in linkage disequilibrium with AR-(CAG)n expanded alleles responsible for spinal bulbar muscular atrophy (SBMA), is rare among our controls; however, the haplotype strategy here described may be used to clarify the origin of expansions in other populations, as in future association studies.

Case-control association study of polymorphisms in the voltage-gated sodium channel genes SCN1A, SCN2A, SCN3A, SCN1B, and SCN2B and epilepsy.

High-frequency action potentials are mediated by voltage-gated sodium channels, composed of one large α subunit and two small ß subunits, encoded mainly by SCN1A, SCN2A, SCN3A, SCN1B, and SCN2B genes in the brain. These play a key role in epilepsy, with the most commonly mutated gene in epilepsy being SCN1A. We examined whether polymorphisms in the above genes affect epilepsy risk in 1,529 epilepsy patients and 1,935 controls from four ethnicities or locations: Malay, Indian, and Chinese, all from Malaysia, and Chinese from Hong Kong. Of patients, 19 % were idiopathic, 42 % symptomatic, and 40 % cryptogenic. We genotyped 43 polymorphisms: 27 in Hong Kong, 28 in Malaysia, and 12 in both locations. The strongest association with epilepsy was rs3812718, or SCN1A IVS5N+5G>A: odds ratio (OR) = 0.85 for allele G (p = 0.0009) and 0.73 for genotype GG versus AA (p = 0.003). The OR was between 0.76 and 0.87 for all ethnicities. Meta-analysis confirmed the association (OR = 0.81 and p = 0.002 for G, and OR = 0.67 and p = 0.007 for GG versus AA), which appeared particularly strong for Indians and for febrile seizures. Allele G affects splicing and speeds recovery from inactivation. Since SCN1A is preferentially expressed in inhibitory neurons, G may decrease epilepsy risk. SCN1A rs10188577 displayed OR = 1.20 for allele C (p = 0.003); SCN2A rs12467383 had OR = 1.16 for allele A (p = 0.01), and displayed linkage disequilibrium with rs2082366 (r (2) = 0.67), whose genotypes tended toward association with SCN2A brain expression (p = 0.10). SCN1A rs2298771 was associated in Indians (OR = 0.56, p = 0.005) and SCN2B rs602594 with idiopathic epilepsy (OR = 0.62, p = 0.002). Therefore, sodium channel polymorphisms are associated with epilepsy.

Folinic acid responsive epilepsy in Ohtahara syndrome caused by STXBP1 mutation.

BACKGROUND: Ohtahara syndrome is a severe condition with early onset of recurrent unprovoked seizures associated with abnormal electroencephalography and global developmental delay. Folinic acid-responsive seizures are treatable causes of Ohtahara syndrome, which is thought to be due to recessive mutations in the ALDH7A1 gene, resulting in deficiency of antiquitin. METHOD: Here we report a girl with Ohtahara syndrome who exhibited transient folinic acid responsiveness but without evidence of antiquitin dysfunction. RESULTS: She was later found to have a known missense mutation (c.1439 C > T, p.P480 L) in exon 16 of the STXBP1 gene. CONCLUSION: For infants presenting with Ohtahara syndrome with responsiveness to folinic acid and negative antiquitin deficiency analyses, genetic testing for other possible causative genes such as STXBP1 mutation is recommended.

Use of dysmorphology for subgroup classification on autism spectrum disorder in Chinese children.

Data from 1,261 Chinese Autistic Spectrum Disorder (ASD) patients were evaluated and categorized into dysmorphic (10.79 %) and non-dysmorphic groups (89.21 %) upon physical examination by the presence of dysmorphic features. Abnormal MRI/CT result, IQ scores and epilepsy were significantly associated with the dysmorphic group of ASD children. However, gender, EEG abnormality and family history and recurrence of ASD were not found to be significantly different between group statuses. It is suggested that results collected from the Chinese population generally resembles that found in the Caucasians with ethnical differences still present. Current study supports the result shown in Miles' study (Miles et al. in Am J Med Genet 135A:171-180, 2005), in which heterogeneity subtypes of autism of different genetic origins which could be distinguished by presence of dysmorphic features on the patients.

Classification of functioning and impairment: the development of ICF core sets for autism spectrum disorder.

Given the variability seen in Autism Spectrum Disorder (ASD), accurate quantification of functioning is vital to studying outcome and quality of life in affected individuals. The International Classification of Functioning, Disability and Health (ICF) provides a comprehensive, universally accepted framework for the description of health-related functioning. ICF Core Sets are shortlists of ICF categories that are selected to capture those aspects of functioning that are most relevant when describing a person with a specific condition. In this paper, the authors preview the process for developing ICF Core Sets for ASD, a collaboration with the World Health Organization and the ICF Research Branch. The ICF Children and Youth version (ICF-CY) was derived from the ICF and designed to capture the specific situation of the developing child. As ASD affects individuals throughout the life span, and the ICF-CY includes all ICF categories, the ICF-CY will be used in this project ("ICF(-CY)" from now on). The ICF(-CY) categories to be included in the ICF Core Sets for ASD will be determined at an ICF Core Set Consensus Conference, where evidence from four preparatory studies (a systematic review, an expert survey, a patient and caregiver qualitative study, and a clinical cross-sectional study) will be integrated. Comprehensive and Brief ICF Core Sets for ASD will be developed with the goal of providing useful standards for research and clinical practice and generating a common language for functioning and impairment in ASD in different areas of life and across the life span.

Arginase deficiency with new phenotype and a novel mutation: contemporary summary.

In areas without expanded newborn screening, instead of presenting neonatally, patients with arginase deficiency typically present with spastic paraplegia in early childhood. Diagnosis of this rare neurometabolic disease poses the first challenge because it is often misdiagnosed as cerebral palsy during initial stages. We describe arginase deficiency in a 20-year-old woman with spastic paraplegia, progressive dystonia, dementia, peripheral neuropathy, epilepsy, liver cirrhosis, and non-B/non-C hepatocellular carcinoma. A novel homozygous mutation NM_000045.2 (ARG1):c.673del (p.Arg225GlyfsX5) was detected. We suggest that all children presenting with progressive neurodegeneration or spastic paraplegia in the absence of risk factors for cerebral palsy should be screened for inborn errors of metabolism, including arginase deficiency. For monitoring urea cycle defects, noninvasive imaging screening for liver fibrosis and hepatocellular carcinoma can help ensure early detection, with potential treatment implications.

Neuromuscular junction acetylcholinesterase deficiency responsive to albuterol.

Congenital myasthenic syndrome caused by endplate acetylcholinesterase deficiency constitutes a rare autosomal recessive disease. We describe a child with early-onset ptosis, complete ophthalmoplegia, facial and proximal muscle weakness, easy fatigability, a decremental electromyographic response, and a repetitive compound muscle action potential not improved by anti-acetylcholinesterase medication. Mutation analysis of the collagenic tail of endplate acetylcholinesterase (COLQ) that encodes the collagenic structural subunit of acetylcholinesterase revealed two canonic splice-site mutations: a previously identified IVS15 + 1G>A mutation and a novel IVS2 - 1G>A mutation. Treatment with albuterol resulted in progressive improvement of muscle strength, exercise tolerance, and ophthalmoplegia. Further studies are needed of the efficacy of albuterol in different types of congenital myasthenic syndrome and the physiologic basis of its beneficial effects.

Mutational origin of Machado-Joseph disease in the Australian Aboriginal communities of Groote Eylandt and Yirrkala.

OBJECTIVE: To determine whether the presence of Machado-Joseph disease (MJD, also spinocerebellar ataxia type 3 [SCA3]) among Australian aborigines was caused by a new mutational event or by the introduction of expanded alleles from other populations. DESIGN: We sequenced a region of 4 kilobases (kb), encompassing the CAG repeat within the ATXN3 gene, in 2 affected Australian aboriginal families and compared them with the Joseph and Machado lineages described before. Full-extended haplotypes (including also more distant single-nucleotide polymorphisms and flanking short tandem repeats) were assessed by segregation and allele-specific amplification. A phylogenetic tree was inferred from genetic distances, and age of the Australasian Joseph-derived lineage was estimated. SETTING: The aboriginal communities of Groote Eylandt and Yirrkala, in the Northern Territories, Australia (local ethics institutional permission was granted, and both community and individual informed consent was obtained). SUBJECTS: A convenience sample of 19 patients and unaffected relatives, from 2 Australian aboriginal families affected with MJD; 40 families with MJD of multiethnic origins and 50 unrelated Asian control subjects. RESULTS: The 2 aboriginal families shared the same full haplotype, including 20 single-nucleotide polymorphisms:TTGATCGAGC-(CAG)(Exp)-CACCCAGCGC, that is, the Joseph lineage with a G variant in rs56268847.Among 33 families with the Joseph lineage, this derived haplotype was found only in 5 of 16 Taiwanese, all 3 Indian,and 1 of 3 Japanese families analyzed. CONCLUSION: A related-extended MJD haplotype shared by Australian aborigines and some Asian families (a Joseph-derived lineage) suggests a common ancestor for all, dating back more than 7000 years.

Expanding phenotype and clinical analysis of tyrosine hydroxylase deficiency.

This study included 12 Chinese patients with a wide spectrum of phenotypes of tyrosine hydroxylase deficiency. Seven females and 5 males, aged 2.2 to 41 years, had phenotypes ranging from severe type with onset at infancy to mild type with onset after 3 years of age. Patients with the severe type had encephalopathy with poor treatment response or infantile parkinsonism with motor delay. Patients with the less common mild type had dopa-responsive dystonia or a newly recognized predominant symptom of myopathy. Female siblings had more severe phenotypes. The phenotype and treatment outcomes were strongly related to a homovanillic acid level and homovanillic acid/5-hydroxyindolacetic acid ratio of less than 1 in the cerebrospinal fluid. Hyperprolactinemia was found in 50% of the severe cases. Levodopa was the mainstay of treatment, and early addition of selegiline resulted in a remarkable response in some patients. Treatment response for mild-type patients is universally good even with a treatment delay of 10 years after onset of neurological symptoms.