Clinical and pathological features of an autosomal dominant, adult-onset leukodystrophy simulating chronic progressive multiple sclerosis.

OBJECTIVE: To study the clinical and pathological features of a kindred with an adult-onset autosomal dominant leukodystrophy. PATIENTS: Five symptomatic and nine asymptomatic at-risk members of the kindred. INTERVENTIONS: Subjects underwent detailed histories and general and neurologic examinations. Further evaluation included electroencephalography, evoked potentials, electromyography, autonomic testing, and analysis of serum, urine, and cerebrospinal fluid. One patient underwent sural nerve biopsy and analysis. Another, previously studied patient, underwent a limited autopsy. RESULTS: Cerebellar and pyramidal dysfunction began in the fourth and fifth decades of life; subtle autonomic symptoms were often present years earlier. Frontal lobe dysfunction and abnormalities of the central visual pathways were mild and of late onset. Sensorineural hearing loss was common. The peripheral nervous system was spared. Autopsy results of one patient revealed severe degeneration of the white matter at all levels of the neuraxis, but most prominent in the frontoparietal and cerebellar regions, with sparing of the subcortical U fibers. Histological and ultrastructural examinations failed to show evidence of a specific pathogenetic mechanism or etiology. CONCLUSION: This disorder seems to be a distinct type of hereditary leukodystrophy, but its exact nature remains unknown.

Computed tomography and magnetic resonance imaging in adult-onset leukodystrophy.

Five clinically affected and nine at-risk members of a kindred with an autosomal dominant adult-onset leukodystrophy simulating chronic progressive multiple sclerosis were studied with computed tomography (CT) and magnetic resonance imaging (MRI). Computed tomographic scans showed white matter lucencies occurring earliest and most prominently in the frontoparietal region. The lesions were nondiscrete, diffuse, and bilaterally symmetric. These changes were more clearly visualized as areas of increased signal intensity with T2-weighted MRI. Magnetic resonance imaging also showed increased signal intensity in the brain stem, cerebellar white matter, or both of four patients. Both MRI and CT differentiated this entity from multiple sclerosis, but MRI was superior to CT in detailing the extent of white matter involvement.

The middle latency auditory evoked potential may be abnormal in dementia.

The P1 potential (50 msec) of the middle latency auditory evoked potential was lacking in 12 of 31 (39%) patients with probable Alzheimer's disease and seven of 12 (58%) demented patients with Parkinson's disease. Component P1 was not present in one normal control subject and one nondemented Parkinson's disease patient. Clinical and experimental evidence suggests that abnormalities of P1 in dementia may be due to cholinergic dysfunction.

Neurologic findings in men with isolated hypogonadotropic hypogonadism.

We studied the neurologic abnormalities in 41 men with isolated hypogonadotropic hypogonadism. Findings included anosmia, hyposmia, mirror movements, ocular motor abnormalities, cerebellar dysfunction, and pes cavus foot deformity. One-third of the subjects had a family history of delayed sexual maturation. Patients with a family history of delayed sexual maturation had a significantly higher incidence of olfactory dysfunction, mirror movements, and pes cavus foot deformity. Our data suggest that isolated hypogonadotropic hypogonadism and its accompanying neurologic abnormalities may arise from a genetically linked developmental abnormality of CNS structures.

Abnormalities in visual spatial attention in men with mirror movements associated with isolated hypogonadotropic hypogonadism.

We studied spatial attentional performance on a visually cued reaction time task in men with isolated hypogonadotropic hypogonadism. A subset of these patients, who displayed mirror movements, have spatial attentional abnormalities. They were slow to respond to targets in the right visual field and especially slow when those targets followed incorrect or diffuse cues. This slowing was present for at least 500 msec after cue onset. They responded equally to targets in the left visual field independent of the spatial cues. The patient population as a whole was significantly faster than controls across all experimental conditions, although the speed of their attentional movement was normal. These data suggest that patients with isolated hypogonadotropic hypogonadism perform reaction time tasks quickly, that faster reaction times do not reflect superior attentional performance, and that a subset of these patients has a spatial attentional abnormality.

Hereditary adult-onset Alexander's disease with palatal myoclonus, spastic paraparesis, and cerebellar ataxia.

We describe a progressive neurologic disorder in three sisters characterized clinically by palatal myoclonus, spastic weakness, hyperreflexia, mild cerebellar dysfunction, and ocular motor abnormalities. Postmortem examination of one patient demonstrated widespread Rosenthal fiber deposition associated with demyelination. The father previously was reported to have similar pathologic findings and carried a clinical diagnosis of multiple sclerosis. These clinical and pathologic findings describe a rare familial leukodystrophy that corresponds most closely to cases reported as adult Alexander's disease. Although similar pathologically to the well-characterized infantile variant of Alexander's disease, it is not known whether this adult variant represents the same disease process.

Diagnosis of multiple sclerosis.

Multiple sclerosis is a demyelinating central nervous system disorder that affects young, otherwise healthy people. Presenting symptoms can be variable; the complaints are often vague and suggestive of a functional disorder. Diagnosis is based mainly on the clinical triad of young age, involvement of two or more areas within the central nervous system, and history characterized by exacerbations and remissions. In selected cases, the diagnosis is aided by cerebrospinal fluid examination, evoked potentials and computed tomographic scanning.

Eye movement disorders in men with isolated hypogonadotropic hypogonadism.

The eye movement abnormalities in two men with isolated hypogonadotropic hypogonadism were studied clinically and electro-oculographically. Both demonstrated striking saccadic dysmetria. Subsequent neuroradiologic investigation confirmed atrophy of the cerebellar vermis in one of the patients. This is in concert with other midline structural abnormalities described in patients with isolated hypogonadotropic hypogonadism and suggests that this syndrome may arise from a genetically linked developmental abnormality of midline central nervous system structures.

Association of a monoamine oxidase B allele with Parkinson's disease.

Monoamine oxidase B (MAO-B) is implicated in the cause of Parkinson's disease (PD) because of its role in metabolizing the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and forming H2O2 during dopamine metabolism. Altered MAO-B activity has been observed in PD platelets. Polymerase chain reaction was used to amplify a portion of the MAO-B gene. Polymerase chain reaction products were screened with restriction enzymes to identify fragments useful for single-stranded conformational polymorphism analysis. A single-stranded conformational polymorphism was identified in an MAO-B polymerase chain reaction product after Hae III digestion. One hundred twenty-one control individuals were allelotyped with frequencies of 0.45 and 0.55 for alleles 1 and 2, respectively. Frequencies of 0.62 and 0.38 (1 and 2, respectively) were observed in a population of 46 patients with PD. The presence of MAO-B allele 1 is associated with a relative risk for PD of 2.03-fold (confidence interval, 1.44-2.61; p < 0.02). For comparison, a monoamine oxidase A polymorphism was used to determine allelic frequencies in these same populations and no statistically significant differences were found. These results suggest that an inherited variant of MAO-B may be involved in a genetic predisposition for PD.

Ophthalmic midline dysgenesis in Kallmann syndrome.

Partial coloboma, observed only with transillumination techniques, occur in 16% of male patients diagnosed with Kallmann syndrome. This sign represents an additional midline defect in this multisystem disorder noted for midline dysgenesis. Its high incidence may be helpful in the diagnosis of this disorder although it does not appear to be the harbinger of any other ocular abnormality.

Primidone/phenobarbital-induced periodic alternating nystagmus.

A 37-year-old man with a history of seizures developed periodic alternating nystagmus (PAN) along with other signs of primidone/phenobarbital toxicity. The PAN gradually diminished in cycle length and intensity, finally resolving with gradual discontinuation of the drugs.

Genetic localization of an autosomal dominant leukodystrophy mimicking chronic progressive multiple sclerosis to chromosome 5q31.

The hereditary leukodystrophies represent a group of neurological disorders, in which complete or partial dysmyelination occurs in either the central nervous system (CNS) and/or the peripheral nervous system. Adult-onset autosomal dominant leukodystrophy (ADLD) is a slowly progressive, neurological disorder characterized by symmetrical widespread myelin loss in the CNS, and the phenotype is similar to that of chronic progressive multiple sclerosis. We report clinical, neuroradiological and neuropathological data from the originally reported ADLD family. Furthermore, we have localized the gene that causes ADLD to a 4 cM region on chromosome 5q31. Linkage analysis of this family yielded a LOD score of 5.72 at theta = 0.0 with the microsatellite marker D5S804. Genetic localization will lead to cloning and characterization of the ADLD gene and may yield new insights into myelin biology and demyelinating diseases.