Novel SACS mutations in autosomal recessive spastic ataxia of Charlevoix-Saguenay type

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset familial disease with prominent myelinated fibers in the optic fundus. ARSACS is frequent in the Charlevoix-Saguenay region of Quebec but rare elsewhere. Mutations in SACS, encoding sacsin, a protein of unknown function, are associated with ARSACS. The authors identified three new SACS mutations in two Italian patients whose phenotype closely matches that of Quebec cases, but without retinal striation.

Clinical and molecular findings in patients with giant axonal neuropathy (GAN)

Giant axonal neuropathy (GAN) is a rare autosomal recessive neurodegenerative disorder of early onset, clinically characterized by a progressive involvement of both peripheral and CNS. The diagnosis is based on the presence of characteristic giant axons, filled with neurofilaments, on nerve biopsy. Recently, the defective protein, gigaxonin, has been identified and different pathogenic mutations in the gigaxonin gene have been reported as the underlying genetic defect. Gigaxonin, a member of the BTB/kelch superfamily proteins, seems to play a crucial role in the cross talk between the intermediate filaments and the membrane network. The authors report clinical and molecular findings in five Italian patients with GAN. This study shows the allelic heterogeneity of GAN and expands the spectrum of mutations in the GAN gene. The frequent occurrence of private mutations stresses the importance of a complete gene analysis.

Mitochondrial alterations in muscle biopsies of patients on statin therapy

Clinical and biopsy study of nine patients on statin therapy suffering from various myopathic syndromes is reported. Biopsy findings showed non specific myopathic signs and mitochondrial changes, such as subsarcolemmal accumulation, morphological alterations, lipid increase and Cox-negative fibers. These findings confirm that statins may cause muscle damage and impair oxidative metabolism.

Early visual function impairment in CADASIL

The authors carried out genetic analyses and visual electrophysiologic evaluations in six asymptomatic sons and daughters of patients with symptomatic cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Three subjects showed Notch3 Cys146Tyr missense mutation and a dysfunction of the outer, middle, and innermost retinal layers, with normal neural conduction in postretinal visual pathways, whereas in the remaining subjects without genetic mutations, no electrophysiologic abnormalities were found. An early vascular retinal impairment in CADASIL may precede the onset of clinical manifestations.

Neurological presentation of Ehlers-Danlos syndrome type IV in a family with parental mosaicism

Ehlers-Danlos syndrome type IV (EDS-IV) is an autosomal-dominant disorder caused by a defect of type III collagen which leads to ruptures of arteries and hollow organs. Neurological presentation with muscle involvement and flexion contractures of the finger joints is uncommon. We clinically characterized seven members of a family with EDS-IV. The index patient, a young woman with an acrogeric face, suffered chronic muscle pain and cramps, Achilles tendon retraction, finger flexion contractures and seizures. The mother had similar features and had experienced an ischemic stroke. Biochemical study in cultured fibroblasts and molecular analysis of the COL3A1 gene led to the diagnosis of EDS-IV. A glycine substitution, p.G883V, within the triple helix of the alpha 1(III) chain, was found in the index patient and in the mother. The maternal grandfather and an aunt each had an abdominal aortic aneurysm, the rupture of which was the cause of death in the latter, at 40 years of age. Surprisingly, we found the mutation, as a mosaic, in the asymptomatic maternal grandmother. This expands the clinical spectrum of EDS type IV and confirms that in some families mosaicism can be identified as the source of the mutation.

Autosomal dominant external ophthalmoplegia and bipolar affective disorder associated with a mutation in the ANT1 gene

The authors report on a family with dominantly inherited progressive external ophthalmoplegia and a diagnostic and statistical manual (fourth revised edition) diagnosis of bipolar psychiatric disorder in several members. Skeletal muscle biopsy from the proposita showed decreased cytochrome c oxidase staining, several ragged-red fibers, and multiple mtDNA deletions. The authors identified a missense mutation (leucine 98-->proline) in the adenine nucleotide translocator 1 gene. The presence of bipolar affective disorder expands the phenotype of adenine nucleotide translocator 1 allelic variants.

Asymptomatic cores and paracrystalline mitochondrial inclusions in CADASIL

Three siblings with genetically assessed cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with core-like lesions and mitochondrial abnormalities in muscles are described. Involvement of the Ryanodine receptor 1 gene was excluded. In the current cases, the relation between molecular genetic lesion and muscle fiber abnormalities remains to be determined, but the Notch3 gene may influence mitochondrial metabolism.

Nemaline myopathy: description of an adult onset case

Nemaline myopathy is a rare congenital muscle disease, with neonatal or adult onset. We report clinical and ultrastructural study of a 73-year-old woman whose symptoms manifested at age 40 years with proximal muscle weakness, nocturnal cramps, muscle pain and walking impairment. Muscle biopsy showed rods and other typical findings suggesting nemaline myopathy. This myopathy should be taken into account in the differential diagnosis of adult onset myopathies. Only ultrastructural examination allows an exact diagnosis.

McLeod neuroacanthocytosis: genotype and phenotype

McLeod syndrome is caused by mutations of XK, an X-chromosomal gene of unknown function. Originally defined as a peculiar Kell blood group variant, the disease affects multiple organs, including the nervous system, but is certainly underdiagnosed. We analyzed the mutations and clinical findings of 22 affected men, aged 27 to 72 years. Fifteen different XK mutations were found, nine of which were novel, including the one of the eponymous case McLeod. Their common result is predicted absence or truncation of the XK protein. All patients showed elevated levels of muscle creatine phosphokinase, but clinical myopathy was less common. A peripheral neuropathy with areflexia was found in all but 2 patients. The central nervous system was affected in 15 patients, as obvious from the occurrence of seizures, cognitive impairment, psychopathology, and choreatic movements. Neuroimaging emphasized the particular involvement of the basal ganglia, which was also detected in 1 asymptomatic young patient. Most features develop with age, mainly after the fourth decade. The resemblance of McLeod syndrome with Huntington's disease and with autosomal recessive chorea-acanthocytosis suggests that the corresponding proteins--XK, huntingtin, and chorein--might belong to a common pathway, the dysfunction of which causes degeneration of the basal ganglia.

PAX6 mutation in a family with aniridia, congenital ptosis, and mental retardation

Congenital aniridia is due to deletions and point mutations in the PAX6 gene. We describe here a case of a mother and her two sons with a syndrome comprising congenital aniridia, ptosis, and slight mental retardation. The sons also show behavioral changes. The possibility of deletion around the PAX6 locus was excluded by polymorphism studies and fluorescence in situ hybridization analysis. Mutation screening of the PAX6 gene revealed the presence of a transversion C719A, resulting in the substitution of arginine for serine at residue 119. We suggest that this missense mutation is responsible both for aniridia and ptosis, and possibly also for the observed cognitive dysfunction in this family.

A conserved sorting-associated protein is mutant in chorea-acanthocytosis

Chorea-acanthocytosis (CHAC, MIM 200150) is an autosomal recessive neurodegenerative disorder characterized by the gradual onset of hyperkinetic movements and abnormal erythrocyte morphology (acanthocytosis). Neurological findings closely resemble those observed in Huntington disease. We identified a gene in the CHAC critical region and found 16 different mutations in individuals with chorea-acanthocytosis. CHAC encodes an evolutionarily conserved protein that is probably involved in protein sorting.

Neuropathological findings associated with retained lead shot pellets in a man surviving two months after a suicide attempt

We describe the neuropathological findings in a 30-year-old man who died two months after attempting suicide with a shotgun. We focused our study on lesions associated with retained lead shot pellets and distant therefrom, as well as lesions distant from the principal site of injury. At the sites of the retained lead shot pellets, we found macrophage proliferation and astrocyte activation, together with axonal spheroids and signs of neuronal damage. In the remaining white matter we observed axonal swellings, astrocyte activation and rarefaction of the neuropil; regressive phenomena of the neurons were also present. All axonal spheroids immunoreacted with antibodies against APP, alphaB-crystallin, NF subunits and ubiquitin. Most reactive astrocytes were positive for GFAP and alphaB-crystallin immunostaining. Some neurons immunoreacting with alphaB-crystallin were also found. These data indicated that an important local reaction developed at the sites of lead shot retention, and mild signs of diffuse axonal damage were found throughout the brain.

The T9176G mtDNA mutation severely affects ATP production and results in Leigh syndrome

The authors identified a novel mtDNA mutation (T9176G) in the ATPase 6 gene in a family in which a 10-year-old girl had a severe neurodegenerative disorder, her elder sister had died of Leigh syndrome (LS), and a maternal uncle had a spinocerebellar disorder. Biochemical studies disclosed a reduced rate of ATP synthesis in skin fibroblast cultures from the proposita as the likely explanation of her severe illness. The findings expand the genetic variants associated with LS.

Ultrastructural findings in the peripheral nerve in a family with the intermediate form of Charcot-Marie-Tooth disease

The authors describe here the ultrastructural findings in peripheral nerve biopsies from two affected members of a family with a previously undescribed intermediate form of Charcot-Marie-Tooth (CMT) disease. We found prevalent demyelinating features such as onion bulbs and myelin splits with uncompacted and irregularly enlarged lamellae, mostly at the Schmidt-Lantermann incisures and in paranodal region. Signs of a chronic axonopathy such as regeneration clusters, large fiber loss, Büngner's bands and unmyelinated fiber involvement were also seen. The presence of both demyelinating and axonal findings, not found in other genetically determined types of CMT disease, confirms the hypothesis of a new nosographic entity of intermediate type.

Visual electrophysiological responses in subjects with cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

OBJECTIVES

To evaluate visual electrophysiological responses in subjects with cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

METHODS

Three subjects (one male and two females, mean age 55.3+/-2.9 years) belonging to an Italian family already diagnosed with CADASIL through clinicopathological and genetic studies and 14 control subjects (6 males and 8 females, mean age 52.7+/-3.6 years) were enrolled in the study. Flash electroretinogram (ERG), oscillatory potentials (OPs) and simultaneous recordings of pattern electroretinogram (PERG) and visual evoked potentials (VEPs) were assessed in all 3 subjects with CADASIL and age-matched controls.

RESULTS

Subjects with CADASIL showed: reduced ERG, OP and PERG (N35-P50, P50-N95) amplitudes with respect to our normal limits; delayed PERG (N35, P50) and VEP (P100) implicit times when compared with our normal limits; and VEP (N75-P100) amplitudes and retinocortical times within our normal limits.

CONCLUSIONS

Subjects with CADASIL present a dysfunction in the outer, middle and innermost retinal layers when the index of neural conduction in the postretinal visual pathways is normal. The delay in visual cortical responses observed in subjects with CADASIL may be ascribable to retinal impairment with a possible functional sparing of the postretinal visual structures.

A novel SURF1 mutation results in Leigh syndrome with peripheral neuropathy caused by cytochrome c oxidase deficiency

We report on a 5-year-old boy with clinical and neuroradiological evidence of Leigh syndrome and peripheral neuropathy. Skeletal muscle biopsy showed decreased cytochrome c oxidase stain. Ultrastructurally, the nerve biopsy showed a defect of myelination. Biochemical analyses of muscle homogenate showed cytochrome c oxidase deficiency (15% residual activity). SURF1 gene analysis identified a novel homozygous nonsense mutation which predicts a truncated surf1 protein.

Autonomic nervous system and smooth muscle cell involvement in systemic sclerosis: ultrastructural study of 3 cases

OBJECTIVE

To investigate morphological abnormalities in nerve and smooth muscle structures of the anorectal wall underlying gastrointestinal dysfunction in patients with systemic sclerosis (SSc).

METHODS

We performed deep rectal biopsy in 3 patients with limited scleroderma of relatively recent onset and intestinal symptoms.

RESULTS

We found ultrastructural signs of axonal degeneration and cytoskeletal abnormalities in the bundles of unmyelinated fibers. There was also focal degeneration of smooth muscle cells, often in association with the presence of partially degranulated mast cells. Many mast cells were also observed in close relation to nerve fibers and vessels. The enteric vessels often showed basal lamina reduplication and hypertrophied endothelial cells with obliterated lumen. No significant fibrosis was found.

CONCLUSION

Our findings indicate early involvement of the autonomic nervous system and to a lesser extent of smooth muscle cells. We confirmed the presence of early vascular lesions and involvement of mast cells in the pathological process.

Type I sialidosis: a clinical, biochemical and neuroradiological study

We report biochemical, morphological and neuroradiological findings in a 40-year-old woman affected with type I sialidosis. The clinical symptoms, consisting of a cerebellar syndrome, were first noted at the age of 17 years. The macular cherry-red spot was first observed after 23 years of disease. A CT scan performed at 21 years of age showed enlargement of the fourth ventricle. Nuclear magnetic resonance imaging of the brain performed at the age of 40 showed severe atrophy of the cerebellum and pontine region; atrophy of cerebral hemispheres and of the corpus callosum was also observed. We emphasize the prolonged course of illness in this patient, observed over a long period of time. Of particular interest is the neuroradiological study showing our findings both at the beginning of the disease and after 20 years.