Infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1)

Autosomal recessive spinal muscular atrophy with respiratory distress type 1 (SMARD1) is the second anterior horn cell disease in infants in which the genetic defect has been defined. SMARD1 results from mutations in the gene encoding the immunoglobulin micro-binding protein 2 (IGHMBP2) on chromosome 11q13. Our aim was to review the clinical features of 29 infants affected with SMARD1 and report on 26 novel IGHMBP2 mutations. Intrauterine growth retardation, weak cry, and foot deformities were the earliest symptoms of SMARD1. Most patients presented at the age of 1 to 6 months with respiratory distress due to diaphragmatic paralysis and progressive muscle weakness with predominantly distal lower limb muscle involvement. Sensory and autonomic nerves are also affected. Because of the poor prognosis, there is a demand for prenatal diagnosis, and clear diagnostic criteria for infantile SMARD1 are needed. The diagnosis of SMARD1 should be considered in infants with non-5q spinal muscular atrophy, neuropathy, and muscle weakness and/or respiratory distress of unclear cause. Furthermore, consanguineous parents of a child with sudden infant death syndrome should be examined for IGHMBP2 mutations.

Genetic epilepsy with febrile seizures plus: Refining the spectrum

OBJECTIVE

Following our original description of generalized epilepsy with febrile seizures plus (GEFS+) in 1997, we analyze the phenotypic spectrum in 409 affected individuals in 60 families (31 new families) and expand the GEFS+ spectrum.

METHODS

We performed detailed electroclinical phenotyping on all available affected family members. Genetic analysis of known GEFS+ genes was carried out where possible. We compared our phenotypic and genetic data to those published in the literature over the last 19 years.

RESULTS

We identified new phenotypes within the GEFS+ spectrum: focal seizures without preceding febrile seizures (16/409 [4%]), classic genetic generalized epilepsies (22/409 [5%]), and afebrile generalized tonic-clonic seizures (9/409 [2%]). Febrile seizures remains the most frequent phenotype in GEFS+ (178/409 [44%]), followed by febrile seizures plus (111/409 [27%]). One third (50/163 [31%]) of GEFS+ families tested have a pathogenic variant in a known GEFS+ gene.

CONCLUSION

As 37/409 (9%) affected individuals have focal epilepsies, we suggest that GEFS+ be renamed genetic epilepsy with febrile seizures plus rather than generalized epilepsy with febrile seizures plus. The phenotypic overlap between GEFS+ and the classic generalized epilepsies is considerably greater than first thought. The clinical and molecular data suggest that the 2 major groups of generalized epilepsies share genetic determinants.

Phenotypic insights into ADCY5-associated disease

Background

Adenylyl cyclase 5 (ADCY5) mutations is associated with heterogenous syndromes: familial dyskinesia and facial myokymia; paroxysmal chorea and dystonia; autosomal‐dominant chorea and dystonia; and benign hereditary chorea. We provide detailed clinical data on 7 patients from six new kindreds with mutations in the ADCY5 gene, in order to expand and define the phenotypic spectrum of ADCY5 mutations.

Methods

In 5 of the 7 patients, followed over a period of 9 to 32 years, ADCY5 was sequenced by Sanger sequencing. The other 2 unrelated patients participated in studies for undiagnosed pediatric hyperkinetic movement disorders and underwent whole‐exome sequencing.

Results

Five patients had the previously reported p.R418W ADCY5 mutation; we also identified two novel mutations at p.R418G and p.R418Q. All patients presented with motor milestone delay, infantile‐onset action‐induced generalized choreoathetosis, dystonia, or myoclonus, with episodic exacerbations during drowsiness being a characteristic feature. Axial hypotonia, impaired upward saccades, and intellectual disability were variable features. The p.R418G and p.R418Q mutation patients had a milder phenotype. Six of seven patients had mild functional gain with clonazepam or clobazam. One patient had bilateral globus pallidal DBS at the age of 33 with marked reduction in dyskinesia, which resulted in mild functional improvement.

Conclusion

We further delineate the clinical features of ADCY5 gene mutations and illustrate its wide phenotypic expression. We describe mild improvement after treatment with clonazepam, clobazam, and bilateral pallidal DBS. ADCY5‐associated dyskinesia may be under‐recognized, and its diagnosis has important prognostic, genetic, and therapeutic implications. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society

Clinical features of conversion disorder

This study reviewed the case notes of 52 children diagnosed as suffering from hysterical conversion during admission to a paediatric teaching hospital over a 10 year period. The disorder was rare below 8 years of age and girls outnumbered boys three to one. Altogether 75% of the children presented during spring and summer; at the time of end of year exams and the beginning of the new school year. The presentation was usually polysymptomatic with gait disturbance being the main complaint in 36 children. Sensory abnormality, predominantly pain, was present in 40 children; this indicates a strong association between psychogenic pain and conversion disorder in children. At discharge 32 were completely recovered or had appreciably improved. There was a core group that presented particular difficulties with diagnosis and showed little positive response to treatment.

Movement disorder emergencies

Movement disorders may present acutely, and failure to recognize and exclude important differential diagnoses can result in significant morbidity or mortality. Unfortunately, much of the literature pertaining to this topic is scattered and not easily accessible. This review aims to address this deficit. Movement disorder emergencies are discussed according to their most likely mode of presentation. Diagnostic considerations and early management principles are reviewed, along with appropriate pathophysiology where relevant.

Status dystonicus and Hallervorden-Spatz disease: treatment with intrathecal baclofen and pallidotomy

Severe dystonia or status dystonicus is a life threatening disorder that develops in patients with both primary and secondary dystonia. We present the case of a 9-year-old boy with Hallervorden-Spatz disease (HVS) who developed status dystonicus, failing to respond to high dose oral therapy with multiple antidystonic agents. High dose intravenous sedating agents combined with endotracheal intubation and mechanical ventilation were required to control the spasms. Alleviation of the spasms was achieved by a combination of temporary intrathecal baclofen infusions and bilateral pallidotomy. Although it could be argued this is a situation where only palliative measures should be used, we believe a relatively aggressive approach was justified. It relieved the intense pain associated with the spasms and allowed the child to be discharged home without the prolonged stay in intensive care, morbidity and mortality, which characterize status dystonicus.

Microdeletions detected using chromosome microarray in children with suspected genetic movement disorders: a single-centre study

AIM

Chromosome microarray (CMA) can determine copy number variants such as microdeletions or microduplications. Microdeletions of movement disorder genes including epsilon-sarcoglycan (SGCE) and thyroid transcription factor-1 (TITF1) have been described in patients with myoclonus dystonia and benign hereditary chorea respectively. We examined whether CMA is a valuable tool in the investigation of children with suspected genetic movement disorders.

METHOD

A genetic movement disorder was suspected if there was a positive first-degree family history, or two or more of the following factors: normal or near-normal magnetic resonance imaging, negative history of brain injury, and negative investigations for metabolic disorders. Tic disorders were excluded. Twenty-five patients (18 males, seven females) with a mean age at movement disorder onset of 4 years 5 month (range 1 mo-14 y) were prospectively recruited with the following primary movement disorders: dystonia (n=10), paroxysmal kinesigenic dyskinesia (n=5), tremor (n=4), chorea (n=3), myoclonus (n=2), and paroxysmal non-kinesigenic dyskinesia (n=1). Comorbid associated features were common, particularly developmental delay or intellectual disability (19 out of 25) and attention-deficit-hyperactivity disorder (six out of 25). CMA was performed using Agilent aCGH 60K array.

RESULTS

Seven out of twenty-five patients had a microdeletion determined by CMA. None of the microdeletions were considered benign variants. Four patients had a deletion of a known movement disorder gene including paroxysmal kinesigenic dyskinesia (PRRT2; n=2), SGCE (myoclonus dystonia, n=1), and TITF1 (benign hereditary chorea, n=1). Three patients had novel microdeletions of unknown but potential significance including 14q13.3 (chorea, n=1), 19p13.12 (tremor, n=1), and 19q13.12 (progressive dystonia). All seven patients had associated neurodevelopmental or behavioural problems.

INTERPRETATION

Assays that determine copy number variants may be a valuable first-tier investigation in patients with suspected genetic movement disorders, particularly when associated with intellectual disability or developmental disorders. Microdeletion syndromes may help the search for new movement disorder genes.

Movement disorders in children with anti-NMDAR encephalitis and other autoimmune encephalopathies

Accurate recognition of movement disorder phenomenology may differentiate children with anti-N-methyl D-aspartate receptor (NMDAR) encephalitis, autoimmune basal ganglia encephalitis (BGE), and Sydenham's chorea (SC). Three neurologists blinded to the diagnoses recorded dominant and associated movement disorders seen on videos of 31 patients with anti-NMDAR encephalitis (n = 10), BGE (n = 12), and SC (n = 9). Stereotypy was only seen in anti-NMDAR encephalitis (8/10) and not in BGE and SC (P < 0.001). Perseveration was only seen in anti-NMDAR encephalitis (5/10) and not in BGE and SC (P < 0.001). Akinesia was more commonly seen in BGE (5/12) than in anti-NMDAR encephalitis (1/10, P = 0.097). Tremor was more commonly seen in BGE (5/12) than in anti-NMDAR encephalitis (1/10, P = 0.097). Chorea was seen in all groups: anti-NMDAR encephalitis (4/10), BGE (3/12), and SC (9/9). Likewise, dystonia was seen in all groups: anti-NMDAR encephalitis (6/10), BGE (7/12), and SC (2/9). Stereotypies or perseveration are suggestive of anti-NMDAR encephalitis, whereas their absence and the presence of akinesia and tremor is more suggestive of BGE. Chorea and dystonia are least discriminating.

Very long chain fatty acids in X-linked adrenoleukodystrophy brain after treatment with Lorenzo's oil

The fatty acid composition of postmortem brain and liver from an adrenoleukodystrophy patient whose diet was supplemented with Lorenzo's oil (glycerol trioleate and glycerol trierucate) for 9 months was determined. The diet depressed plasma and liver saturated very long chain fatty acids (24:0 and 26:0) and increased plasma and liver erucic (22:1) and nervonic (24:1) acids. The levels of plasma linoleic (18:2 n-6), eicosopentaenoic (20:5 n-3), and docosahexaenoic (22:6 n-3) acids were also reduced, while the biochemical marker for essential fatty acid deficiency (20:3 n-9) was markedly increased in liver. However, we were unable to detect any corresponding changes in brain indicating that little erucic acid crossed the blood-brain barrier. Our findings suggest that dietary supplementation with Lorenzo's oil is of limited value in correcting the accumulation of saturated very long chain fatty acids in the brain of patients with adrenoleukodystrophy.

Familial paroxysmal exercise-induced dystonia: atypical presentation of autosomal dominant GTP-cyclohydrolase 1 deficiency

Paroxysmal exercise-induced dystonia (PED) is one of the rarer forms of paroxysmal dyskinesia, and can occur in sporadic or familial forms. We report a family (male index case, mother and maternal grandfather) with autosomal dominant inheritance of paroxysmal exercise-induced dystonia. The dystonia began in childhood and was only ever induced after many minutes of exercise, and was never present at rest, or on initiation of movements. In addition, family members suffered restless legs syndrome (RLS), depression, and adult-onset Parkinsonism. The index case had low cerebrospinal fluid neurotransmitters and pterins. The PED and RLS stopped on initiation of L-Dopa therapy. Both live family members were found to have a nonsense mutation (p.E84X) in exon 1 of the GTP-cyclohydrolase 1 (GCH-1) gene. We propose that GCH-1 mutations should be considered a genetic cause of familial PED, especially if additional clinical features of monoaminergic deficiency are present in affected individuals.

The value of partial sleep deprivation as a routine measure in pediatric electroencephalography

For more than 50 years it has been known that in patients with epilepsy, sleep markedly increases the diagnostic yield of the electroencephalogram (EEG). Sleep deprivation could have an additional activating role. Many laboratories do not use these methods routinely but reserve them for a second EEG if equivocal or negative findings are present in the initial EEG. We studied a regime of routine partial sleep deprivation without the use of hypnotic agents in 396 children younger than age 17 years who were referred for EEG with a diagnosis of epilepsy or suspected epilepsy. Sleep was achieved for the EEG in 77% (96% in the 1 month to 2 year age group, 78% in the 2 to 8 year age group, and in 64% of those more than 8 years old). In a comparison group of 72 children who had not been sleep-deprived, sleep was achieved in 44% (69% of those less than 2 years old, 27% of those between 2 and 8 years of age, and 33% of those older than 8 years). The differences were highly significant. The regime was well tolerated. Routine partial sleep deprivation is a practical and effective method of obtaining sleep and thus maximizing the information obtained from a single EEG.

Hypomyelination with atrophy of the basal ganglia and cerebellum: Follow-up and pathology

BACKGROUND AND OBJECTIVE

Hypomyelination with atrophy of the basal ganglia and cerebellum is a recently defined disorder. Only a few patients have been described. We report on 11 additional patients and new MRI findings and provide histopathologic confirmation of the MRI interpretation.

METHODS

We reviewed the patients' clinical history and present findings. We scored the MRI abnormalities. The histopathology of one patient was re-examined.

RESULTS

The patients' early psychomotor development was normal or delayed, followed by increasing extrapyramidal movement abnormalities, ataxia, and spasticity. Mental capacities were variably affected. MRI showed hypomyelination with, on follow-up, evidence of further myelin loss and variable white matter atrophy. The putamen was small or, more often, absent; the head of the caudate nucleus was decreased in size. In contrast, the thalamus and globus pallidus remained normal. Cerebellar atrophy was invariably present. Histopathology confirmed the myelin deficiency, probably related to both lack of deposition and low-grade further loss. The degeneration of putamen was subtotal. The cerebellar cortex was affected, particularly the granular layer.

CONCLUSION

Hypomyelination with atrophy of the basal ganglia and cerebellum is a syndrome diagnosed by distinctive MRI findings. Histopathology confirms hypomyelination, low-grade further myelin loss, subtotal degeneration of the putamen, and cerebellar cortical atrophy. All known patients are sporadic, and the mode of inheritance is unclear.

A subgroup of spinocerebellar ataxias defective in DNA damage responses

A subgroup of human autosomal recessive ataxias is also characterized by disturbances of eye movement or oculomotor apraxia. These include ataxia telangiectasia (A-T); ataxia telangiectasia like disorder (ATLD); ataxia oculomotor apraxia type 1 (AOA1) and ataxia oculomotor apraxia type 2 (AOA2). What appears to be emerging is that all of these have in common some form of defect in DNA damage response which could account for the neurodegenerative changes seen in these disorders. We describe here sensitivity to DNA damaging agents in AOA1 and evidence that these cells have a defect in single strand break repair. Comparison is made with what appears to be a novel form of AOA (AOA3) which also shows sensitivity to agents that lead to single strand breaks in DNA as well as a reduced capacity to repair these breaks. AOA3 cells are defective in the DNA damage-induced p53 response. This defect can be overcome by incubation with the mdm2 antagonists, nutlins, but combined treatment with nutlins and DNA damage does not enhance the response. We also show that AOA3 cells are deficient in p73 activation after DNA damage. These data provide further evidence that different forms of AOA have in common a reduced capacity to cope with damage to DNA, which may account for the neurodegeneration observed in these syndromes.

Expanding CEP290 mutational spectrum in ciliopathies

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.

Mutations in the cyclic adenosine monophosphate response element of the tyrosine hydroxylase gene

Tyrosine hydroxylase (TH) deficiency (OMIM 191290) is one cause of early-onset dopa-responsive dystonia. We describe seven cases from five unrelated families with dopa-responsive dystonia and low homovanillic acid in cerebrospinal fluid who were suspected to suffer from TH deficiency. Analysis of part of the TH promotor showed five homozygous and two heterozygous mutations in the highly conserved cyclic adenosine monophosphate response element. Our data suggest that, if no mutations are found in the coding regions of the gene in patients strongly suspected of TH deficiency, the search for pathogenic mutations should be extended to regulatory promotor elements.

Congenital fibrosis of the extraocular muscles associated with cortical dysplasia and maldevelopment of the basal ganglia

BACKGROUND

Congenital fibrosis of the extraocular muscles (CFEOM) is a rare condition that has been traditionally regarded as a primary eye muscle disease. Recent studies, however, suggest that CFEOM may be the result of a primary neuropathy with secondary myopathic changes.

PURPOSE

To describe a previously unrecognized association between congenital fibrosis of the extraocular muscles and structural abnormalities of the brain.

DESIGN

Small case series.

METHODS

Detailed clinical examinations and neuroradiologic studies were performed on the three affected family members. In addition, genetic analysis of the family was performed.

RESULTS

The three affected family members, mother and two children, have the ocular features of 'classic' congenital fibrosis of the extraocular muscles. All showed dilation of the left lateral ventricle secondary to hypoplasia of the body and tail of the ipsilateral caudate nucleus. There was fusion of an enlarged caudate nucleus head with the underlying putamen. Both children showed widespread bilateral cortical dysplasia. Genetic analysis of the family was inconclusive but consistent with linkage to the CFEOM1 locus on chromosome 12. Chromosomal analysis of the affected individuals did not show evidence of a deletion of chromosome 12 and haplotype analysis was not suggestive of a microdeletion.

CONCLUSIONS

Cerebral cortical and basal ganglia maldevelopment can be found in individuals with CFEOM. This suggests that neuroimaging should be considered in the initial diagnostic evaluation of these patients, particularly if there is developmental delay.

Athetosis II: the syndrome of mild athetoid cerebral palsy

We describe 8 patients who presented with continuous, irregular movements occurring independently in individual fingers and, in some cases, toes, in the setting of mild dystonia present since early childhood and not associated with major disability. The finger movements varied from low-amplitude quivering or wriggling to larger amplitude movements in the plane of abduction-adduction as well as flexion-extension; they were asymmetrical but not unilateral. Quivering or working of the facial muscles was seen in 5 patients. Most patients reported worsening of the movements over the years, but there was no other evidence of a progressive neurological disease. We classify the movement disorder as athetosis as described by Hammond and Shaw and the syndrome as mild athetoid cerebral palsy.

PEHO and PEHO-like syndromes: report of five Australian cases

PEHO syndrome is a rare progressive infantile encephalopathy with onset within the first few months of life. Few patients fulfilling the diagnostic criteria for PEHO syndrome have been reported outside Finland. Affected infants have facial dysmorphism and suffer from severe hypotonia, profound mental retardation, convulsions (often with a hypsarrhythmic EEG pattern), transient or persistent peripheral oedema, and optic atrophy. Cerebellar and brainstem atrophy are usually present on neuroimaging. A PEHO-like syndrome has been described, in which the affected individuals have neither optic atrophy nor the typical neuroradiological findings. We report five Australian patients, the first with classical features of PEHO syndrome, and four who have a PEHO-like disorder. We compare their features with other published cases. We suggest that PEHO or a PEHO-like syndrome may affect more patients than are currently identified, based on the original diagnostic criteria for this disorder.

Roseola infantum and other syndromes associated with acute HHV6 infection

Eight cases of acute human herpesvirus type 6 (HHV6) infection in infants were diagnosed serologically by the demonstration of IgM anti-HHV6 (8/8) and a significant change in total anti-HHV6 antibody titre (6/8). Four infants were sufficiently ill to require admission to hospital and further investigations: one with encephalitis and three with gross hepatosplenomegaly, two of whom had evidence of simultaneous infection with another herpes-virus. The remaining four infants had an illness compatible with roseola infantum, although this diagnosis had not been made clinically. Sera from two of those infants with rash had been sent for analysis to exclude rubella because the infants' mothers were pregnant. The other two had received antibiotics when febrile, and the subsequent appearance of the roseola rash had raised the possibility of antibiotic allergy. The data suggest that there are clinical syndromes in addition to roseola infantum associated with the presence of IgM anti-HHV6, in which serological screening for evidence of acute HHV6 infection may be useful.