Thoracic spinal stenosis associated with renal osteodystrophy. Diagnosis based on magnetic resonance imaging and computed tomography.

We describe a case of thoracic myelopathy in a patient with renal osteodystrophy. The patient had chronic renal failure for longer than 20 years and had skeletal changes indicative of renal osteodystrophy, before the onset of myelopathy. Association between spinal stenosis and this entity has been documented only once before in the lumbar region.

The natural history of amyotrophic lateral sclerosis.

Using 42 strength and functional assessments recorded monthly, the natural history of amyotrophic lateral sclerosis (ALS) is described in 167 patients (98 men, 67 women) followed in five medical centers in the western United States. The mean age at onset was 57.4 years, and symptoms were present for 2.

Evidence of genetic heterogeneity among the nondystrophic myotonias.

Recent in vitro electrophysiologic studies have demonstrated abnormal sodium channel gating in muscle from patients with Thomsen's disease and have called the chloride hypothesis into question. Abnormal sodium channel function, like myotonia, is a feature common to Thomsen's disease and several myotonias that are genetically linked to a chromosome-17q sodium channel locus. We present a pedigree segregating an allele for Thomsen's disease that is unlinked to this sodium channel locus, thus constituting evidence of genetic heterogeneity among the nondystrophic myotonias.

Genetic mapping of chronic childhood-onset spinal muscular atrophy to chromosome 5q11.2-13.3.

SPINAL muscular atrophy (SMA) describes a group of heritable degenerative diseases that selectively affect the alpha-motor neuron. Childhood-onset SMAs rank second in frequency to cystic fibrosis among autosomal recessive disorders, and are the leading cause of heritable infant mortality. Predictions that genetic heterogeneity underlies the differences between types of SMA, together with the aggressive nature of the most-severe infantile form, make linkage analysis of SMA potentially complex.

The femoral head notch.

A notch-like defect at the vertex of the proximal femoral ossification center is a normal variant in children. This has often been mistaken for Legg-Perthes disease. This sharply defined defect is distinct from the irregular epiphyseal ossification patterns common in other areas.