Paroxysmal kinesigenic dyskinesia and infantile convulsions: clinical and linkage studies.

OBJECTIVE: To clinically characterize affected individuals in families with paroxysmal kinesigenic dyskinesia (PKD), examine the association with infantile convulsions, and confirm linkage to a pericentromeric chromosome 16 locus. BACKGROUND: PKD is characterized by frequent, recurrent attacks of involuntary movement or posturing in response to sudden movement, stress, or excitement. Recently, an autosomal dominant PKD locus on chromosome 16 was identified. METHODS: The authors studied 11 previously unreported families of diverse ethnic background with PKD with or without infantile convulsions and performed linkage analysis with markers spanning the chromosome 16 locus. Detailed clinical questionnaires and interviews were conducted with affected and unaffected family members. RESULTS: Clinical characterization and sampling of 95 individuals in 11 families revealed 44 individuals with paroxysmal dyskinesia, infantile convulsions, or both. Infantile convulsions were surprisingly common, occurring in 9 of 11 families. In only two individuals did generalized seizures occur in later childhood or adulthood. The authors defined a 26-cM region using linkage data in 11 families (maximum lod score 6.63 at theta = 0). Affected individuals in one family showed no evidence for a shared haplotype in this region, implying locus heterogeneity. CONCLUSIONS: Identification and characterization of the PKD/infantile convulsions gene will provide new insight into the pathophysiology of this disorder, which spans the phenotypic spectrum between epilepsy and movement disorder.

Bilateral predominant radial nerve crutch palsy. A case report.

Axillary crutch palsy, although well described in the literature, is rarely seen in clinical practice. Little has been written in the contemporary orthopaedic literature. The purpose of this case report is to report on a well-documented axillary crutch palsy with bilateral, predominantly radial, nerve dysfunction that resolved spontaneously in eight weeks.

Fine structure of cortical tubers in tuberous sclerosis: a Golgi study.

The fine structure of cerebral cortex, including cortical tubers, was studied in 3 patients with tuberous sclerosis. Tubers were found to consist of two predominant cell populations, astroglia and small multipolar (stellate) neurons. Both cell types tended to form aggregates within tubers, with glia more prominent in the subpial region. The stellate neurons of tubers had beaded or varicose dendrites with few dendritic spines. The findings suggest that neurons within tubers are an aberrant primitive cell type that fails to express the pyramidal cell shape and dendritic morphology that is characteristic of normal human neocortex. Cortex intervening between tubers had basically normal dendritic morphology. However, quantitative study showed a decrease in the length of dendritic branches of pyramidal neurons, as also observed in several other conditions manifested by mental retardation.

Auditory brain-stem responses in hydrocephalic patients.

Auditory brain-stem response (ABR) was measured in 40 patients (80 ears) with confirmed hydrocephalus. Eighty-eight percent of these patients showed some form of ABR abnormality. Responses indicative of brain-stem dysfunction consisted of prolonged I-V interwave latency (38%), reduced V/I amplitude ratio (33%), and abnormalities in wave-shape of components III (27%) and V (53%). In addition, 70% of the patients had elevated ABR thresholds; 45% had responses in excess of 20 dB HL and the remaining 25% had no ABR activity. The etiology of the hydrocephalus, head circumference and brain-stem symptoms were not associated with particular ABR abnormalities. Communicating hydrocephalus correlated significantly with both prolonged I-V conduction time and absence of ABR activity, compared with non-communicating hydrocephalus. Four of the 9 patients retested showed ABR improvement on follow-up; one patient showed deterioration. The results were compared to our prior studies of ABR in 60 post-meningitic patients and in 100 severely neurologically impaired institutionalized children in whom the incidence of intrinsic brainstem abnormalities was one-third and two-thirds that of the hydrocephalic group, respectively. The results of this study suggest that ABR can be used to document clinically unsuspected brain-stem pathology that may accompany hydrocephalus. Auditory brain-stem dysfunction is likely to complicate the assessment of hearing sensitivity in hydrocephalic patients.