Clinical findings and a therapeutic trial in the first patient with beta-ureidopropionase deficiency.

The clinical, neurophysiological and neuroradiological work-up as well as the results of a specific treatment trial are presented of the first patient diagnosed with beta-ureidopropionase deficiency (E.C. 3.5.1.6, McKusick 606673). The patient presented with an early-onset dystonic movement disorder, severe developmental delay with marked impairment of visual responsiveness in combination with severely delayed myelination in magnetic resonance imaging studies. In addition, there were partial optic atrophy, pigmentary retinopathy and mild cerebellar hypoplasia. The enzyme defect was expected to lead to intracerebral deficiency of beta-alanine which seems to be a neuromodulator at inhibitory synapses. Therefore, a therapeutic trial with supplementation of beta-alanine was undertaken over 1.5 years with no convincing clinical improvement.

Fumarase deficiency presenting with periventricular cysts.

A fumarase-deficient patient expressed a novel phenotype of congenital cerebral ventricular dilatation and periventricular cysts. The patient was a compound heterozygote for two mutations that are the only ones among the 12 published mutations that have been found in multiple, unrelated, fumarase-deficient patients.

Long-term noninvasive ventilation in children and adolescents with neuromuscular disorders.

The aim of the current study was to investigate the long-term impact of nocturnal noninvasive (positive-pressure) ventilation (NIV) on sleep, sleep-disordered breathing (SDB) and respiratory function in children and adolescents with progressive neuromuscular disorders (NMD). Thirty patients (12.3 +/- 4.1 yrs) with various inherited NMD were treated with NIV for ventilatory insufficiency (n=14) or symptomatic SDB (n=16). Patients were prospectively followed with sleep studies, spirometry and peak inspiratory muscle pressure. Ten patients were studied before and after 3 nights withdrawal from NIV. NIV normalised nocturnal gas exchange in all patients and diurnal gas exchange in patients with ventilatory insufficiency. The effects persisted over 25.3 +/- 12.7 months. Nocturnal transcutaneous partial pressure of carbon dioxide improved from (baseline versus latest control) 7.1 +/- 1.3 to 5.5 +/- 0.6 kPa (53.7 +/- 9.9 to 41.6 +/- 4.8 mmHg), diurnal carbon dioxide arterial tension from 6.3 +/- 1.6 to 5.4 +/- 0.5 kPa (47.5 +/- 11.9 to 40.6 +/- 3.6 mmHg). NIV improved respiratory disturbance index, arousals from sleep, nocturnal heart rate and sleep architecture. Vital capacity decreased in five adolescents with Duchenne muscular dystrophy -183 +/- 111 mL x yr(-1) but remained stable in 25 children with other conditions (8 +/- 78 mL x yr(-1)). Three nights withdrawal of NIV in 10 previously stable patients resulted in prompt deterioration of SDB and gas exchange back to baseline but could be instantly normalised by resumption of NIV. Noninvasive (positive-pressure) ventilation has favourable long-term impact on nocturnal and diurnal gas exchange and sleep and in patients with non-Duchenne neuromuscular disorders on vital capacity as well. It is indicated in children and adolescents with symptomatic sleep-disordered breathing or ventilatory insufficiency due to neuromuscular disorders.

Introduction of a ketogenic diet in young infants.

The ketogenic diet is a rational treatment for pyruvate dehydrogenase complex deficiency (McKusick 312170) and GLUT1 deficiency syndrome (McKusick 138140). An increasing number of patients are diagnosed in early infancy, but few data are available on the introduction of a ketogenic diet in this age group. GLUT1 deficiency syndrome was suspected in four infants presenting with seizures and unexplained hypoglycorrhachia. A ketogenic diet was introduced at 6-28 weeks of age. Ketosis was initiated by fasting, monitored by bedside blood glucose and 3-hydroxybutyrate determinations, and was maintained successfully using supplemented carbohydrate-free infant formula and emulgated triglycerides. All patients developed ketosis within 24 h. 3-Hydroxybutyrate concentrations available at the bedside correlated inversely with the base excess. At glucose levels < or = 40 mg/dl patients remained asymptomatic in the presence of ketones. The ketogenic formula was tolerated well, parental compliance was good, and all patients remained seizure-free on the diet. GLUT1 deficiency was confirmed in two patients; the diet was discontinued in the other two patients. In one infant, failure to thrive on medium-chain triglycerides was effectively reversed using long-chain triglycerides. Urine dipstick analyses failed to detect ketosis in another infant. Adverse effects of the diet were limited to renal stones in one patient. The ketogenic diet can be introduced and maintained successfully in young infants using long-chain fat emulsion. Monitoring 3-hydroxybutyrate at the bedside was useful for metabolic control and superior to urine dipstick analysis. Seizure control was effective and adverse effects were limited, but evaluation of the long-term effects of the ketogenic diet in this age group must await ongoing studies.

Wheat kernel ingestion protects from progression of muscle weakness in mdx mice, an animal model of Duchenne muscular dystrophy.

A simple, reproducible test was used to quantify muscle weakness in mdx mice, an animal model of Duchenne muscular dystrophy. The effect of bedding on wheat kernels and of dietary supplementation of alpha-tocopherol on the progression of muscle weakness was investigated in mdx mice. When measured during the first 200 d of life, mdx mice developed muscle weakness, irrespective of bedding and diet. When kept on wood shavings and fed a conventional rodent diet, mdx mice showed progressive muscle weakness over the consecutive 200 d, and eventually showed a significant weight loss during the next 200-d observation period. Progression of muscle weakness and weight loss were almost completely prevented in mdx mice that were kept on wheat kernel bedding. In contrast, only incomplete maintenance of muscle strength and body weight was observed in mdx mice kept on wood shavings and fed the alpha-tocopherol-supplemented diet. It is concluded from these experiments that a component of wheat kernels other than alpha-tocopherol is essential to prevent the progression of muscle weakness in mdx mice.

Myopathy in Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS) is a disorder of unknown aetiology. The classical features of the syndrome include a typical ('elfin') facies, mental retardation and heart defects. Myopathy has not so far been part of the spectrum of WBS. We studied six patients with WBS aged 3-25 years, five of whom showed clinical and morphological evidence of myopathy. The clinical manifestations of myopathy included hypotonia in infancy, walking delay, joint contractures, scoliosis, and increased exhaustion on exertion. These symptoms were present in variable expression but part of a typical postural pattern. Examination of muscle biopsies showed lipid storage in four patients and increased variability of fibre size in three. In one patient a muscle biopsy gave normal results. Biochemical investigation in four patients with morphological evidence of lipid storage in muscle revealed muscle carnitine deficiency in three. In addition, enzyme activities of fatty acid beta-oxidation were low in one of two specimens tested. It is concluded that a clinically relevant myopathy is part of the multi-system manifestation of WBS and a clinical trial of carnitine supplementation is justified.

Damage of thalamus and basal ganglia in asphyxiated full-term neonates.

Thalamic-striatal damage of symmetric bilateral distribution was found in four severely asphyxiated neonates born at term. Two patients showed evidence of bilateral thalamic-striatal necrosis and two showed hemorrhage of the same distribution. The four patients had a common history of prolonged asphyxia in the neonatal period combined with severe acidosis and respiratory insufficiency. The outcome was lethal in all children. Three patients survived for some time and showed additional evidence of generalized brain damage including cortical necrosis and subcortical leucomalacia and one patient was found to have intravital calcification of the putamen at 14 days of age. The appearance of thalamic-striatal damage in US, CCT and NMR imaging is discussed. Thalamic-striatal damage may not be detectable by US until several days after the initial insult. US does not permit a distinction between necrosis and hemorrhage, but CCT and NMR imaging may be successful. Only five infants with a comparable pattern of brain damage due to asphyxia have been described so far. Our own studies seem to indicate that thalamic-striatal damage is the hallmark of more widespread brain damage, and that it will be found more frequently if carefully looked for in asphyxiated neonates born at term.