No abstract

Mutations in the gene for the ganglioside-induced differentiation-associated protein-1 (GDAP1) on 8q21 recently were reported to cause autosomal recessive Charcot-Marie-Tooth (CMT) sensorimotor neuropathy. Neurophysiology and nerve pathology were heterogeneous in these cases: a subset of GDAP1 mutations was associated with peripheral nerve demyelination, whereas others resulted in axonal degeneration. In this study, we identified two novel mutations disrupting the GDAP1 reading frame. Homozygosity for a single base pair insertion in exon 3 (c.349_350insT) was observed in affected children from a Turkish inbred pedigree. The other novel allele detected in a German patient was a homozygous mutation of the intron 4 donor splice site (c.579 + 1G>A). Patients with GDAP1 mutations displayed severe, early childhood-onset CMT neuropathy with prominent pes equinovarus deformity and impairment of hand muscles. Nerve conduction velocities were between 25 and 35 m/s and peripheral nerve pathology showed axonal as well as demyelinating changes. These findings fitted the definition of intermediate type CMT and further support the view that GDAP1 is vital for both, axonal integrity and Schwann cell properties.

Neurological complications of Epstein-Barr virus (EBV) have been reported almost exclusively in the course of acute primary infections. The role of EBV in paediatric neurological disease was investigated prospectively over a 2-year period, searching for acute primary, chronic, and reactivated EBV infections. Active EBV infections were diagnosed in 10/48 patients, including two with acute primary EBV infections (cranial neuritis and cerebellitis), one with chronic active infection (T/NK cell lymphoma with cranial neuritis), and seven with reactivated infections. Among these seven patients, three showed "Alice in Wonderland" syndrome, one facial nerve palsy, one progressive macrocephaly, and two prolonged encephalitic illness. The prognosis was good except for the patient with lethal T/NK cell lymphoma and the two girls with encephalitic illness. Despite steroid treatment, these girls suffered prolonged cognitive impairment and epileptic seizures. Both developed left-sided hippocampal atrophy, and one of them hippocampal sclerosis. Like primary infections, reactivated EBV infections cause neurological complications in a considerable number of paediatric patients, lead to serious long-term complications, and may contribute to the pathogenesis of hippocampal lesions.

No abstract

Using a recently developed noninvasive EMG recording technique with multi-electrode arrays we investigated the pattern and distribution of motor unit action potentials (MUAP) following maximal voluntary contraction of the musculus abductor pollicis brevis. An additional parameter, i.e. muscular conduction velocity (CV) in single motor units, was calculated from the multi-electrode array EMG recordings. From 63 healthy children of various age the normal EMG pattern and CV were derived and compared to the EMG of diagnosed patients known to suffer from Duchenne muscular dystrophy and from spinal muscular atrophy. In normal individuals the muscular CV in neonates was lowest at 1-2 m/s and gradually reached a plateau of 2.9-4 m/s from the age of 4 years onwards. The EMG in 31 children with Duchenne muscular dystrophy showed an abnormal pattern with low amplitude action potentials. In 30 out of 31 patients a significantly lower muscular CV was found. In 10 children with spinal muscular atrophy the EMG showed action potentials of abnormally large amplitude and a reduced recruitment of firing motor units. The muscular CV remained within the normal range. Compared to classical needle EMG the application of this new noninvasive EMG technique in children is painless and offers an easy-to-handle diagnostic tool to differentiate between neuromuscular diseases of denervating or of myopathic origin.