Facioscapulohumeral muscular dystrophy defect identified

A neurovascular complication after scapulothoracic arthrodesis

Facioscapulohumeral muscular dystrophy is a progressive disorder characterized by weakness in the muscles of the face, shoulder girdle and upper limbs, and variable lower extremity weakness. The muscles that stabilize the scapula are significantly weak, although the deltoid usually is preserved. With attempted shoulder abduction, the unstable scapula protrudes, elevates, and internally rotates. Scapulothoracic arthrodesis stabilizes the scapula and improves active range of motion and function of the shoulder. Appropriate scapular positioning on the chest wall has been described previously. The current authors review a neurovascular complication after scapulothoracic arthrodesis in which the scapula was positioned as described in the literature. Immediate repositioning resulted in an excellent long-term outcome. Previous recommendations as to scapular position must be taken simply as guidelines. Intraoperative monitoring of neurovascular function in the upper extremity should prevent this complication.

Sensory ataxic neuropathy as the presenting feature of a novel mitochondrial disease

Four unrelated patients presented with a severe sensory ataxic neuropathy in association with dysarthria and chronic progressive external ophthalmoplegia. Electrophysiologic and pathologic studies showed severe axonal loss disproportionately affecting sensory nerves. Molecular genetic analysis revealed multiple mitochondrial DNA deletions in muscle and peripheral nerve. Sensory ataxic neuropathy may be the predominant and presenting manifestation of a mitochondrial disorder, and a mitochondrial etiology should be included in its differential diagnosis. The triad of sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO) may represent a novel mitochondrial disease associated with multiple mitochondrial DNA deletions.

A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer's disease

A 1-year, double-blind, placebo-controlled, randomized, parallel-group study compared the efficacy and safety of acetyl-L-carnitine hydrochloride (ALCAR) with placebo in patients with probable Alzheimer's disease (AD). Subjects with mild to moderate probable AD, aged 50 or older, were treated with 3 g/day of ALCAR or placebo (1 g tid) for 12 months. Four hundred thirty-one patients entered the study, and 83% completed 1 year of treatment. The Alzheimer's Disease Assessment Scale cognitive component and the Clinical Dementia Rating Scale were the primary outcome measures. Overall, both ALCAR- and placebo-treated patients declined at the same rate on all primary and most secondary measures during the trial. In a subanalysis by age that compared early-onset patients (aged 65 years or younger at study entry) with late-onset patients (older than 66 at study entry), we found a trend for early-onset patients on ALCAR to decline more slowly than early-onset AD patients on placebo on both primary endpoints. In addition, early-onset patients tended to decline more rapidly than older patients in the placebo groups. Conversely, late-onset AD patients on ALCAR tended to progress more rapidly than similarly treated early-onset patients. The drug was very well tolerated during the trial. The study suggests that a subgroup of AD patients aged 65 or younger may benefit from treatment with ALCAR whereas older individuals might do more poorly. However, these preliminary findings are based on past hoc analyses. A prospective trial of ALCAR in younger patients is underway to test the hypothesis that young, rapidly progressing subjects will benefit from ALCAR treatment.

Exclusion mapping of chromosomal regions which cross hybridise to FSHD1A associated markers in FSHD1B

Facioscapulohumeral muscular dystrophy (FHSD) is a genetically heterogeneous, autosomal dominant primary disease of muscle. The predominant form of FSHD, which has been designated FSHD1A, has been localised to the 4q34 region of human chromosome 4. The disease locus (loci) for the remaining FSHD families, which are not linked to chromosome 4 and have been designated FSHD1B, has not yet been identified.

The D4F104S1 marker which detects copies of a 3·2 kb tandem repeat (D4Z4) which contains several types of repetitive sequences, including Hox gene-like elements, has been shown to be closely linked to the chromosome 4 FHSD disease locus. The loss of an integral number of the 3·2 kb tandem repeats has been associated with FSHD1A. When hybridised to chromosomal spreads these sequences cross hybridise with heterochromatin on acrocentric chromosomes and specific areas of human chromosomes 1, 3, and 10. Potentially these specific regions of cross hybridisation may be linked to FSHD1B. To examine this possiblity we have carried out linkage studies in our largest FSHD1B family. In this paper we exclude these areas of specific cross hybridisation as disease loci for FSHD1B.

The frequency of patients with 50-kd dystrophin-associated glycoprotein (50DAG or adhalin) deficiency in a muscular dystrophy patient population in Japan: immunocytochemical analysis of 50DAG, 43DAG, dystrophin, and utrophin

The 50-kd dystrophin-associated glycoprotein (50DAG or adhalin) in the skeletal muscle has been shown to be deficient in patients with severe childhood autosomal recessive muscular dystrophy prevalent in North Africa. To elucidate the frequency of patients having the 50DAG deficiency in a muscular dystrophy population in Japan, we immunocytochemically examined 50DAG, 43DAG, dystrophin, and utrophin. A total of 243 patients with muscular dystrophy, among 1,035 diagnostic muscle biopsies during the past 2.5 years, were analyzed. We identified five unrelated patients (three females and two males who have no family history) with 50DAG deficiency in the sarcolemma. Thus, 2.1% (5/243) of our muscular dystrophy patient population had 50DAG deficiency.

A large pedigree with early-onset Alzheimer's disease: clinical, neuropathologic, and genetic characterization

We present clinical, neuropsychological, and neuropathologic data on a large pedigree including 34 subjects with early-onset progressive dementia. The mean (+/- SD) age at onset was 46 +/- 3.5 years and the mean age at death 52.6 +/- 5.7 years. Twelve patients were clinically diagnosed as having probable Alzheimer's disease (AD) according to the NINCDS-ADRDA criteria. Neuropsychological evaluation, performed at a moderate stage of the disease, was available in six subjects and showed a classic pattern of cognitive deficit. Myoclonus and extrapyramidal signs were common, and seizures were present in all affected subjects. There were neuropathologic changes typical of AD in two brains. A significant lod score of 5.48 was observed at a recombination fraction of theta = 0.0 with the genetic marker D14S43, thereby establishing that the responsible gene was located on chromosome 14q24.3. These results suggest that epilepsy could represent a particular feature in AD families linked to chromosome 14q.

Facioscapulohumeral muscular dystrophy: the impact of genetic research

Recent developments in genetic research have led to the localization and identification of the causative gene defect in a large number of neurological diseases. This paper describes some of the basic principles of molecular genetics and the strategies that have been followed in the search for the gene for facioscapulohumeral muscular dystrophy (FSHD), beginning with the recent localization to chromosome 4q. Many questions remain concerning the pathogenesis and possible genetic heterogeneity of this autosomal dominant myopathy. Hitherto, most evidence favours a genetically homogeneous disorder, but only the isolation and detailed characterization of the FSHD gene will resolve these issues completely.