Post-Anoxic Reticular Reflex Myoclonus in a Child and Proposed Classification of Post-Anoxic Myoclonus.

OBJECTIVE: We describe a child with post-anoxic myoclonus of the reticular reflex type and discuss the classification of post-anoxic myoclonus. PATIENT DESCRIPTION: A nine-year-old boy with severe hypoxic-ischemic encephalopathy due to submersion developed early epileptic spasms followed by stimulus sensitive multifocal generalized myoclonus and later dystonia. Video electromyography (EMG) polygraphy performed before treatment demonstrated that the discharges associated with the myoclonus lasted less than 50 milliseconds. Cortical myoclonus was excluded by jerk-locked averaging using arm muscles, which showed no cortical correlates. The recruitment order on EMG polygraphy was consistent with a brainstem generator for the myoclonus, characteristic of reticular reflex myoclonus. Both myoclonus and dystonia responded to clonazepam. He remains in a persistent vegetative state. CONCLUSIONS: Reticular reflex myoclonus can be demonstrated by detailed neurophysiological assessment in children as in adults, and it has a similar poor prognosis in children. Post-anoxic myoclonus can have several mechanisms and should not be considered synonymous with Lance-Adams myoclonus.

Treatable childhood neuronopathy caused by mutations in riboflavin transporter RFVT2.

Childhood onset motor neuron diseases or neuronopathies are a clinically heterogeneous group of disorders. A particularly severe subgroup first described in 1894, and subsequently called Brown-Vialetto-Van Laere syndrome, is characterized by progressive pontobulbar palsy, sensorineural hearing loss and respiratory insufficiency. There has been no treatment for this progressive neurodegenerative disorder, which leads to respiratory failure and usually death during childhood. We recently reported the identification of SLC52A2, encoding riboflavin transporter RFVT2, as a new causative gene for Brown-Vialetto-Van Laere syndrome. We used both exome and Sanger sequencing to identify SLC52A2 mutations in patients presenting with cranial neuropathies and sensorimotor neuropathy with or without respiratory insufficiency. We undertook clinical, neurophysiological and biochemical characterization of patients with mutations in SLC52A2, functionally analysed the most prevalent mutations and initiated a regimen of high-dose oral riboflavin. We identified 18 patients from 13 families with compound heterozygous or homozygous mutations in SLC52A2. Affected individuals share a core phenotype of rapidly progressive axonal sensorimotor neuropathy (manifesting with sensory ataxia, severe weakness of the upper limbs and axial muscles with distinctly preserved strength of the lower limbs), hearing loss, optic atrophy and respiratory insufficiency. We demonstrate that SLC52A2 mutations cause reduced riboflavin uptake and reduced riboflavin transporter protein expression, and we report the response to high-dose oral riboflavin therapy in patients with SLC52A2 mutations, including significant and sustained clinical and biochemical improvements in two patients and preliminary clinical response data in 13 patients with associated biochemical improvements in 10 patients. The clinical and biochemical responses of this SLC52A2-specific cohort suggest that riboflavin supplementation can ameliorate the progression of this neurodegenerative condition, particularly when initiated soon after the onset of symptoms.

Methods of standing from supine and percentiles for time to stand and to run 10 meters in young children.

OBJECTIVE: To assess the method and time to stand from supine and the time to run 10 m for normal young children. STUDY DESIGN: Three hundred twenty-one normal children aged 2.8-7.8 years were recruited from primary schools. After standardization, each test was carried out twice, timed, and videoed. The influence of age, sex, height, weight, body mass index (BMI), and method of standing were analyzed. Charts for time to stand and running time were produced and assessment of reproducibility performed. RESULTS: For the time to stand from supine and the method used, there was a significant correlation with age. More than 50% of young children took >2 seconds. There was no significant association with BMI. Method of standing was associated with standing time in boys but not in girls. A Bland-Altman plot of standing times by 2 observers showed good reproducibility with no clinically significant difference. For the 10-m running test, there was a significant negative correlation with age, height, weight, and BMI. CONCLUSION: There is considerable variability in the method used and time taken to stand from supine in young children. These change with age, permitting the creation of charts showing age-related normal values.

Corticosteroid treatment of behaviour, language and motor regression in childhood disintegrative disorder.

Childhood disintegrative disorder (CDD) (ICD-10 F84.3) is defined by a period of normal development before onset followed by gradual loss of previously acquired skills with the development of characteristic abnormalities of social, communicative and behavioural functioning. We report two children with apparent CDD, who showed amelioration of behaviour, language and motor regression after corticosteroid treatment.

Acute central and peripheral demyelination associated with Mycoplasma pneumoniae.

A 7-year-old female presented with Mycoplasma pneumoniae pneumonitis and a progressive ascending limb paralysis. She developed severe respiratory distress, requiring ventilation, and became apparently unresponsive with fixed dilated pupils. Peripheral nerves were inexcitable in nerve-conduction studies. Magnetic resonance imaging of the brain revealed evidence of extensive demyelination. Anti-GM1 immunoglobulin M antibody titers were raised. She improved after a second course of intravenous immunoglobulin and eventually made a full recovery.