W.O. Renier

A 4–base pair deletion in the mitochondrial cytochrome b gene associated with parkinsonism/MELAS overlap syndrome

Five patients with diminished activity of complex III of the mitochondrial respiratory chain have been screened for mutations in the mitochondrial cytochrome b (cyt b) gene. In 1 patient, a young boy with an akinetic rigid syndrome and a mitochondrial encephalomyopathy with lactic acidosis and stroke‐like episodes (MELAS), a novel 4–base pair deletion was identified. This mutation in this highly conserved gene is considered to be pathogenic since it is a heteroplasmic frame shift mutation predicted to lead to a truncated protein. Ann Neurol 1999;45:130–133

Familial congenital hydrocephalus and aqueduct stenosis with probably autosomal dominant inheritance and variable expression.

A kindred is reported on with suspected autosomal dominant congenital hydrocephalus and aqueduct stenosis. In contrast to patients with X-linked congenital hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS) our patients were not mentally retarded and they did not show any pyramidal tract dysfunction or clasped thumbs; the pyramids were not affected either, as was confirmed by autopsy, CT or MRI. Molecular genetic studies in our patients have not revealed abnormalities of eight exons of the L1 neural adhesion molecule gene that is related to HSAS.

A dysbalanced immune system in cryptogenic Lennox-Gastaut syndrome

In children with cryptogenic Lennox‐Gastaut syndrome we found a functionally impaired humoral immune response to a primary antigen (haemocyanin), despite signs of a triggered immune system consisting of elevated IgG concentrations. This combination of immunological findings, considered to be the expression of a dysbalanced‐triggered as well as functionally impaired‐immune system, has also been described in an auto‐immune disease like systemic lupus erythaematodes in humans, and in genetically epilepsy‐prone rats. The interactions between the immune system and the nervous system in Lennox‐Gastaut syndrome will be discussed.

Polyglucosan bodies in intramuscular motor nerves

SummaryThe presence of polyglucosan bodies was studied in intramuscular motor nerves of 292 muscle biopsies. These biopsies were classified into five diagnostic categories and investigated for the presence of polyglucosan bodies in relation to age and sex. Their presence was nonspecific in patients over 20 years, the only correlation being with ageing. Under 20 years, their presence pointed to the diagnosis of Laforas disease. In cases in which both a muscle biopsy and a sural nerve biopsy were performed, the former appeared to contain these polyglucosans more frequently.

Neuropathological findings in muscle-eye-brain disease (MEB-D)

SummaryCongenital muscular dystrophy (CMD) associated with cerebro-ocular dysplasia named muscle-eye-brain disease (MEB-D) is described in two sisters. Progressive hypotonia, mental retardation and severe visual failure appeared immediately after birth. Pathological examination demonstrated muscular dystrophy, hydrocephalus, type II lissencephaly and defective eye development of foetal origin. The great similarity of the clinical and neuropathological picture of both sisters is in agreement with an autosomal recessive inheritance. Neuropathological distinction between Fukuyama-CMD and MEB-D is a more severe and earlier cerebral developmental defect and the association with ocular dysplasia in MEB-D.

Chronic inflammatory demyelinating polyneuropathy in two siblings.

A familial occurrence of chronic inflammatory demyelinating polyneuropathy is reported. The diagnostic problems in distinguishing the progressive form of this disease in childhood from hereditary motor and sensory neuropathy types I and III are discussed. Criteria for a definite diagnosis of chronic inflammatory demyelinating polyneuropathy are proposed.

Congenital muscular dystrophy and severe central nervous system atrophy in two siblings

Severe degenerative features of the nervous system of a hitherto unknown kind, associated with a neuromuscular disorder with histopathological features of congenital muscular dystrophy, are reported in two female siblings. The clinical profile was characterized by generalized hypotonia followed by spastic tetraplegia, contractures, polyneuropathy, lack of cognitive development and progressive microcephaly. There was no involvement of the eyes. Neuropathological examination of the brain of one sibling, who died at the age of 30 months, revealed subtotal loss of neurons in the cerebral and cerebellar cortex and in the ventral pons, and secondary loss of myelin in the cerebral and cerebellar subcortical white matter. Sural nerve biopsy in the other sibling, who had a similar neurological affection, showed a lack of large myelinated fibers.

Laminin-α2 (merosin), β-dystroglycan, α-sarcoglycan (adhalin), and dystrophin expression in congenital muscular dystrophies : An immunohistochemical study

Muscle biopsies of 13 congenital muscular dystrophy (CMD) patients were investigated for the expression of laminin-a2 (merosin), b-dystroglycan, a-sarcoglycan (adhalin) and dystrophin. Expression of these proteins was normal in six out of eight patients with pure-CMD, in three non-Japanese patients clinically resembling Fukuyama-CMD (F-CMD), and in two patients with Walker‐Warburg syndrome (WWS). The two ‘pure’-CMD patients with white matter hypodensity showed severely decreased laminin-a2 expression and normal expression of the other proteins. Our findings in the non-Japanese patients, clinically resembling F-CMD, are different from those in Japanese cases with F-CMD in the literature. Consequently, our patients suffer from WWS or from another yet undetermined form of CMD.

A mitochondrial encephalomyopathy with a partial cytochrome c oxidase deficiency of muscle.

A 16 year old girl showed delayed psychomotor development. In infancy, exercise intolerance, cerebellar signs, deteriorated with increasing intercurrent infections, and disturbances of breathing and cardiac rhythm became manifest. From the age of 7 years there was chronic progressive psychomotor deterioration, with hypotonia, a bilateral pyramidal and cerebellar syndrome, and mild epilepsy. CSF pyruvate and lactate levels were elevated, and lactate content was elevated in the urine. There was an abnormally high rise of lactate levels on moderate exercise and an abnormal response to pyruvate loading. Quadriceps muscle biopsies obtained at age 10 and 16 years showed ragged-red fibres, and a decreased cytochrome c oxidase activity and cytochrome aa3 content. Cytochrome c oxidase activity in fibroblasts was normal. Clinical signs and symptoms in association with a disturbance of mitochondrial energy metabolism led us to diagnosis of probable Leigh syndrome.

GM2-gangliosidosis. Clinical and biochemical aspects of four cases.

We discuss four cases of GM2-gangliosidosis. In one of them the biochemical diagnostic confirmation was difficult. This case revealed striking discrepancies between the results of different methods of enzyme assay. The hexosaminidase A determination based on pH inactivation is not always reliable; assay with natural substrate may be necessary. However, the results with the newly developed substrate 4-MU-GlcNac-6-SO4 are promising and it seems to be a good alternative to the traditional (pH or heat) inactivation procedures. The deficiency can be shown in leukocytes, plasma and fibroblasts with the 6-sulfated substrate. The carrier state seems better reflected in plasma hexosaminidase A than in leukocyte hexaminidase A levels.