A retrospective review of X-linked Charcot-Marie-Tooth disease in childhood.

OBJECTIVE: X-linked Charcot-Marie-Tooth disease (CMTX) is infrequently diagnosed in childhood, and its clinical and neurophysiologic features are not well-described. We reviewed clinical, neurophysiologic, and pathologic findings in 17 children with CMTX. METHODS: This was a retrospective review of children with CMTX from 2 tertiary pediatric hospitals. The diagnosis of CMTX was based on an identifiable connexin 32 mutation (CMTX1) or a consistent pedigree and neurophysiologic features in children without a connexin 32 mutation (CMTX-other). RESULTS: Six boys and 2 girls from 8 kindreds had CMTX1, and 8 boys and 1 girl from 5 kindreds had other forms of CMTX (CMTX-other). Fifteen children, including males and carrier females, were symptomatic from infancy or early childhood (younger than 5 years). In addition to the typical Charcot-Marie-Tooth disease clinical phenotype, some patients had delayed motor development, sensorineural hearing loss, tremor, pathologic fractures, or transient CNS disturbances. Eleven children underwent nerve conduction studies. Median nerve motor nerve conduction velocities were in the intermediate to normal range (30-54 m/s) in all children older than 2 years. Axon loss, reflected by low-amplitude compound muscle action potentials, was present in all patients. A pattern of X-linked dominant inheritance, with carrier females showing an abnormal neurologic or neurophysiologic examination, correlated with the presence of a connexin 32 mutation in all but 2 pedigrees. CONCLUSIONS: The clinical phenotype of CMTX is broader than previously reported. Onset in males and carrier females is most often in early childhood. Families with an X-linked dominant inheritance pattern are likely to have CMTX1.

Determinants of reduced health-related quality of life in pediatric inherited neuropathies.

OBJECTIVE: We have shown that health-related quality of life (QOL) in children with inherited neuropathies (Charcot-Marie-Tooth disease [CMT]) is significantly reduced compared to population norms, thus establishing its utility as an outcome measure in therapeutic trials. However, the Australian ascorbic acid trial in children with CMT type 1A (CMT1A) identified no change in QOL scores despite a trend toward improvement in nerve conduction velocities in the treated group. The objective of this study was to identify clinical, electrophysiologic, and functional correlates of QOL in children with CMT1A, to guide future investigations of strategies to improve QOL and reduce disability in these patients. METHODS: In this cross-sectional study, a series of multivariate regression models were developed to determine whether QOL scores could be explained by demographic and symptom data, standardized measures of gross motor function, foot/ankle and hand/finger involvement, electrophysiology, and gait characteristics in 70 children aged 5-16 years with CMT1A. RESULTS: Independent determinants of reduced QOL in children with CMT1A, from strongest to weakest, were leg cramps, hand tremor, short step length, reduced long jump distance, ankle inflexibility, poor agility and endurance, advancing age, and foot drop. Many of the standardized clinical and electrophysiologic measures used as endpoints in clinical trials of CMT correlated poorly with QOL. CONCLUSION: QOL is negatively affected by CMT1A in children. Multivariate modeling suggests that interventions designed to improve leg cramps, tremor, agility, endurance, and ankle flexibility might have a substantial effect on QOL in children with CMT1A.

Autosomal dominant congenital spinal muscular atrophy--a possible developmental deficiency of motor neurones?

We describe a kindred with an unusual congenital lower motor neuron disorder with significant but static muscle weakness predominantly affecting the lower limbs. The proband had talipes equinovarus and congenital hip contractures and did not walk until 19 months of age. Lower-extremity predominant, primarily proximal weakness was identified on assessment at three years. Over a 20 year follow-up there has been no clinical progression. The proband has a four-year-old daughter with very similar clinical findings. Electromyography and muscle biopsy suggest reduced numbers of giant normal duration motor units with little evidence of denervation or reinnervation. Dominant congenital spinal muscular atrophy predominantly affecting the lower limbs is rarely described. It is possible that the disorder is due to a congenital deficiency of motor neurons.

Severe early-onset axonal neuropathy with homozygous and compound heterozygous MFN2 mutations.

OBJECTIVE: Severe early-onset axonal neuropathy (SEOAN) is a heterogeneous phenotype first delineated by Ouvrier et al., characterized by progressive axonal degeneration with gait problems often progressing to wheelchair requirement and later respiratory involvement. Most cases are sporadic single cases. Some have heterozygous mitofusin 2 (MFN2) mutations, many of which are de novo dominant mutations. The aim of this study was to investigate the mode of inheritance in three individuals with severe early-onset axonal neuropathy and homozygous or compound heterozygous MFN2 mutations. METHODS: The clinical and molecular findings in the parents of three individuals with SEOAN with homozygous or compound heterozygous MFN2 mutations were examined. RESULTS: All parents were asymptomatic or mildly symptomatic with some signs of peripheral neuropathy indicating a minimal phenotype. Two had hearing problems. All parents carried the relevant single base (heterozygous) MFN2 variations. CONCLUSION: Severe early-onset axonal neuropathy due to MFN2 mutations can present as an apparently recessively inherited neuropathy but the minimal phenotype in the parents suggests a semi-dominant mechanism.

Interventions for the prevention and treatment of pes cavus.

BACKGROUND: People with pes cavus frequently suffer foot pain, which can lead to significant disability. Despite anecdotal reports, rigorous scientific investigation of this condition and how best to manage it is lacking. OBJECTIVES: To assess the effects of interventions for the prevention and treatment of pes cavus. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Register (April 2007), MEDLINE (January 1966 to April 2007), EMBASE (January 1980 to April 2007), CINAHL (January 1982 to April 2007), AMED (January 1985 to April 2007), all EBM Reviews (January 1991 to April 2007), SPORTdiscuss (January 1830 to April 2007) and reference lists of articles. We also contacted known experts in the field to identify additional published or unpublished data. SELECTION CRITERIA: We included all randomised and quasi-randomised controlled trials of interventions for the treatment of pes cavus. We also included trials aimed at preventing or correcting the cavus foot deformity. DATA COLLECTION AND ANALYSIS: Two authors independently selected papers, assessed trial quality and extracted data. MAIN RESULTS: Only one trial (custom-made foot orthoses) fully met the inclusion criteria. Two additional cross-over trials (off-the-shelf foot orthoses and footwear) were also included. Both studies assessed secondary biomechanical outcomes less than three-months after randomisation. Data used in the three studies could not be pooled due to heterogeneity of diagnostic groups and outcome measures. The one trial that fully met the inclusion criteria investigated the treatment of cavus foot pain in 154 adults over a three month period. The trial showed a significant reduction in the level of foot pain, measured using the validated 100-point Foot Health Status Questionnaire, with custom-made foot orthoses versus sham orthoses (WMD 10.90; 95% CI 3.21 to 18.59). Furthermore, a significant improvement in foot function measured with the same questionnaire was reported with custom-made foot orthoses (WMD 11.00; 95% CI 3.35 to 18.65). There was also an increase in physical functioning of the Medical Outcomes Short Form - 36 (WMD 9.50; 95% CI 4.07 to 14.93). There was no difference in reported adverse events following the allocation of custom-made (9%) or sham foot orthoses (15%) (RR 0.61; 95% CI 0.26 to 1.48). AUTHORS' CONCLUSIONS: In one randomised controlled trial, custom-made foot orthoses were significantly more beneficial than sham orthoses for treating chronic musculoskeletal foot pain associated with pes cavus in a variety of clinical populations. There is no evidence for any other type of intervention for the treatment or prevention of foot pain in people with a cavus foot type.

Lesch-Nyhan disease in a 20-year- old man incorrectly described as developing 'cerebral palsy' after general anaesthesia in infancy.

Lesch-Nyhan disease (LND) is a rare X-linked recessive genetic disorder caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme. The classic clinical condition is characterized by cognitive impairment, hypotonia at rest, choreoathetosis, hyperuricaemia and the hallmark symptom of severe and involuntary self-mutilation. We describe a man with LND who was initially thought to have suffered from a dyskinetic cerebral palsy after an uncomplicated inguinal herniorrhaphy under general anaesthesia at 5 1/2 months of age. In the absence of overt self-injurious behaviour, the diagnosis was not considered for nearly two decades. The diagnosis of LND was established at 20 years of age through clinical review, biochemical examinations and molecular analysis. HPRT haemolysate activity was 7.6% of the normal control, suggesting that he had a milder variant of the disease. Mutation analysis of the HPRT gene revealed a novel missense mutation, c.449T > G in exon 6 (p.V150G). Cascade testing of family members revealed that the mother was heterozygous for the mutation but two siblings (a brother and a sister) did not carry the sequence mutation. Whether the onset of neurological abnormalities in this particular case can be attributed to the general anaesthesia is discussed.

The Australian Childhood Dementia Study.

OBJECTIVES: To estimate the prevalence of childhood dementia, identify aetiological factors, and provide a brief survey of the psychosocial impact of childhood dementia. METHOD: The Australian Paediatric Surveillance Unit (APSU) was used to identify children with dementia. A total of 224 cases were notified about the dementia study and 141 (63%) questionnaires were completed and returned. Ascertainment was restricted to those most likely to have progressive neurocognitive decline because of practitioner bias against reporting non-progressive cases as dementia. RESULTS: Eighty children with dementia were identified. The estimated prevalence for dementia in childhood in Australian was 5.6/100,000. Thirteen cases (16%) were notified before the age of two years. Seventeen (21%) children were reported to have uncertain or unknown aetiology. Impact upon day to day family functioning was reported by clinicians to be 'marked' or 'extreme' in 50 (63%) families. Only four (6%) clinicians judged present services to be 'very adequate', while 16 (20%) clinicians judged current psychological support for the needs of the family to be 'very' or 'moderately inadequate'. Dementia as an overarching diagnostic concept offers integrative possibilities for research, management and service planning and provision. Childhood disintegrative disorder as a concept is criticised.

The expanding phenotype of laminin alpha2 chain (merosin) abnormalities: case series and review.

Initial reports of patients with laminin alpha2 chain (merosin) deficiency had a relatively homogeneous phenotype, with classical congenital muscular dystrophy (CMD) characterised by severe muscle weakness, inability to achieve independent ambulation, markedly raised creatine kinase, and characteristic white matter hypodensity on cerebral magnetic resonance imaging. We report a series of five patients with laminin alpha2 deficiency, only one of whom has this severe classical CMD phenotype, and review published reports to characterise the expanded phenotype of laminin alpha2 deficiency, as illustrated by this case series. While classical congenital muscular dystrophy with white matter abnormality is the commonest phenotype associated with laminin alpha2 deficiency, 12% of reported cases have later onset, slowly progressive weakness more accurately designated limb-girdle muscular dystrophy. In addition, the following clinical features are reported with increased frequency: mental retardation (~6%), seizures (~8%), subclinical cardiac involvement (3-35%), and neuronal migration defects (4%). At least 25% of patients achieve independent ambulation. Notably, three patients with laminin alpha2 deficiency were asymptomatic, 10 patients had normal MRI (four with LAMA2 mutations reported), and between 10-20% of cases had maximum recorded creatine kinase of less than 1000 U/l. LAMA2 mutations have been identified in 25% of cases. Sixty eight percent of these have the classical congenital muscular dystrophy, but this figure is likely to be affected by ascertainment bias. We conclude that all dystrophic muscle biopsies, regardless of clinical phenotype, should be studied with antibodies to laminin alpha2. In addition, the use of multiple antibodies to different regions of laminin alpha2 may increase the diagnostic yield and provide some correlation with severity of clinical phenotype.

Mutations in the gene encoding immunoglobulin mu-binding protein 2 cause spinal muscular atrophy with respiratory distress type 1.

Classic spinal muscular atrophy (SMA) is caused by mutations in the telomeric copy of SMN1. Its product is involved in various cellular processes, including cytoplasmic assembly of spliceosomal small nuclear ribonucleoproteins, pre-mRNA processing and activation of transcription. Spinal muscular atrophy with respiratory distress (SMARD) is clinically and genetically distinct from SMA. Here we demonstrate that SMARD type 1 (SMARD1) results from mutations in the gene encoding immunoglobulin micro-binding protein 2 (IGHMBP2; on chromosome 11q13.2-q13.4). In six SMARD1 families, we detected three recessive missense mutations (exons 5, 11 and 12), two nonsense mutations (exons 2 and 5), one frameshift deletion (exon 5) and one splice donor-site mutation (intron 13). Mutations in mouse Ighmbp2 (ref. 14) have been shown to be responsible for spinal muscular atrophy in the neuromuscular degeneration (nmd) mouse, whose phenotype resembles the SMARD1 phenotype. Like the SMN1 product, IGHMBP2 colocalizes with the RNA-processing machinery in both the cytoplasm and the nucleus. Our results show that IGHMBP2 is the second gene found to be defective in spinal muscular atrophy, and indicate that IGHMBP2 and SMN share common functions important for motor neuron maintenance and integrity in mammals.

Severe infantile axonal neuropathy with respiratory failure.

We describe 5 infants (4 male, 1 female) with a severe intractable form of motor-sensory axonal neuropathy. All became ventilator-dependent, 4 have since died and 1 remains static. Diaphragmatic paralysis was an early feature with generalized neuropathy evolving rapidly. Nerve conduction studies and biopsies were consistent with axonal disease. This disorder could be a new condition or part of the spectrum of inherited neuropathies of the axonal degenerative type. It may be that there is a "switching-off" in the infant's Schwann cell-axonal interactions in utero or in the early postnatal period, resulting in severe progressive deterioration and then a static period without recovery.

Anterior horn cell disease and olivopontocerebellar hypoplasia.

To date, fewer than 30 cases of anterior horn cell disease with associated olivopontocerebellar hypoplasia have been reported. We describe five patients and review the literature on this uncommon disorder. In addition to a syndrome of progressive spinal muscular atrophy similar to that seen in Werdnig-Hoffmann disease, this disorder is characterised by hypoplasia of the olivary nuclei, pons, and cerebellum. Additional clinical features may include dysmorphism, abnormal eye movements, stridor, congenital joint contractures, and enlarged kidneys. Pontocerebellar hypoplasia may be associated with posterior fossa cystic malformations, cerebral atrophy, and a demyelinating neuropathy.

Childhood chronic inflammatory demyelinating polyneuropathy: clinical course and long-term outcome.

We reviewed the clinical history, electrophysiologic and pathologic findings, and response to therapy of 16 children with chronic inflammatory demyelinating polyneuropathy. The majority presented with lower limb weakness. Sensory loss was uncommon. The illness was monophasic in seven children, relapsing in six, and three had a slowly progressive course. All patients were treated with immunosuppressive agents. In 11, the initial treatment was prednisolone. All had at least a short-term response but five went on to develop a relapsing course. Intravenous immunoglobulin was the initial treatment in four patients. Three responded rapidly, with treatment being stopped after a maximum of 5 months. In resistant chronic inflammatory demyelinating neuropathy, in addition to prednisolone and immunoglobulin, plasma exchange, azathioprine, cyclosporine, methotrexate, cyclophosphamide and pulse methylprednisolone were tried at different times in different patients. On serial neurophysiologic testing slowing of nerve conduction persisted for long periods after clinical recovery. Follow-up was for an average of 10 years. When last seen 14 patients were asymptomatic, two having mild residual deficits. Childhood chronic inflammatory demyelinating neuropathy responds to conventional treatment and generally has a favourable long-term outcome.

Clinical syndromes associated with tomacula or myelin swellings in sural nerve biopsies.

OBJECTIVES: To describe the neuropathological features of clinical syndromes associated with tomacula or focal myelin swellings in sural nerve biospies and to discuss possible common aetiopathological pathways leading to their formation in this group of neuropathies. METHODS: Fifty two patients with sural nerve biopsies reported to show tomacula or focal myelin swellings were reviewed, light and electron microscopy were performed, and tomacula were analysed on teased fibre studies. Molecular genetic studies were performed on those patients who were available for genetic testing. RESULTS: Thirty seven patients were diagnosed with hereditary neuropathy with liability to pressure palsies (HNPP), four with hereditary motor and sensory neuropathy type I (HMSN I) or Charcot-Marie-Tooth disease type 1 (CMT1), four with HMSN with myelin outfolding (CMT4B), three with IgM paraproteinemic neuropathy, three with chronic inflammatory demyelinating polyneuropathy (CIDP), and one with HMSN III (CMT3). CONCLUSIONS: Most of these syndromes were shown to be related to genetic or immunological defects of myelin components such as peripheral myelin protein 22 (PMP22), myelin protein zero (P0), or myelin associated glycoprotein (MAG). These proteins share the HNK-1 epitope which has been implicated in cell adhesion processes. Impaired myelin maintenance may therefore contribute to the formation of tomacula and subsequent demyelination.

SYSTEMS: School-Years Screening Test for the Evaluation of Mental Status.

This paper introduces the School-Years Screening Test for Evaluation of Mental Status (SYSTEMS). It was designed to be used by neurologists, pediatricians, and other health professionals assessing children with suspected cognitive problems or changes. SYSTEMS was initially based on the adult Mini-Mental State Examination developed by Folstein, Folstein, and McHugh in 1975. SYSTEMS is a 7- to 12-minute, one-on-one interview test containing 46 items for use in children between 5 and 12 years of age. Although a full diagnosis cannot be made, the results do provide an indication of whether to send a child for further detailed cognitive assessment. The development of SYSTEMS comprised seven studies with a total of 1207 children involved from Sydney primary schools and neurology clinics of the New Children's Hospital, Westmead, New South Wales, Australia. All children were administered the SYSTEMS. Some of the children also were administered the Stanford-Binet Intelligence Test, 4th edition, or the Differential Ability Scales. Results showed that the SYSTEMS was internally consistent, unbiased by sex, socioeconomic indicators, or language groups; discriminated well by age; and strongly correlated (r = 0.88) with mental age. No significant differences in results obtained by two trained administrators were evident and no indication of apparent practice effect was found. The SYSTEMS was found to have desirable levels of sensitivity (83% and 92%), specificity (76% and 95%), and likelihood ratio for cognitive impairment (3.63 and 17.5) when compared with neurologic judgments and the Differential Ability Scales, respectively.

Influenza A encephalitis with movement disorder.

Influenza A is an uncommon but well-recognized cause of viral encephalitis in childhood, occurring most commonly during community influenza outbreaks. The authors report four cases of influenza A encephalitis that occurred during an Australian epidemic in 1997-1998. Choreoathetosis during the acute phase of infection or basal ganglia involvement on neuroimaging was observed in three of the four patients. These findings in pediatric encephalitis are suggestive of influenza A infection and may guide investigation and early diagnosis.

A novel syndrome of episodic muscle weakness maps to xp22.3.

We describe a family with a novel disorder characterized by episodic muscle weakness and X-linked inheritance. Eight males in three generations demonstrate the characteristic features of the disorder. Episodes of severe muscle weakness are typically precipitated by febrile illness and affect the facial and extraocular musculature, as well as the trunk and limbs, and resolve spontaneously over a period of weeks to months. Younger members of the family are normal between episodes but during relapses show generalized weakness, ptosis, and fluctuations in strength. In some cases, fatigability can be demonstrated. The proband has late-onset chronic weakness and fatigability. The clinical phenotype has features suggestive both of the congenital myasthenic syndromes and of ion-channel disorders such as the periodic paralyses. We have localized the responsible gene to chromosome Xp22.3, with a maximum two-point LOD score of 4. 52 at a recombination fraction of.0, between OACA2 and DXS9985.