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Biomedical subjects

B G Comings

Publications and source records attributed to B G Comings.

24 records · Page 2Linked to original sources
PubMed1986

Evidence for an X-linked modifier gene affecting the expression of Tourette syndrome and its relevance to the increased frequency of speech, cognitive, and behavioral disorders in males.

A number of disorders affecting speech, learning, and behavior have a 3:1 or greater male:female ratio. This has usually been explained on the basis of a developmental model postulating a difference in the young male versus female brain. Tourette syndrome is a hereditary neurobehavioral disorder due to a single major autosomal gene. It is associated with learning disorders and attention deficit disorder with hyperactivity and shows a similar predilection for males. Because of the more obvious nature of the tics and vocal noises, it is uniquely suited for examining an alternative hypothesis of an X-linked modifying gene to account for the increased incidence in males. Two alternative models tested were an autosomal modifying gene and the developmental model. Family pedigrees on a series of 430 consecutive cases of Tourette syndrome with 966 age-corrected offspring were used to compare the observed affected and unaffected sons and daughters for nine different phenotype matings with the expected ratios for three different models. The X-linked modifier model provided a better fit to the observed data and accounted for marked differences in the percentage of affected sons and daughters when the father versus the mother transmitted the Tourette syndrome gene. A similar model may account for the male predominance in other genetically influenced disorders of speech, learning, and behavior.

Cognition Disorders↗
PubMed1985

Tourette syndrome: clinical and psychological aspects of 250 cases.

Tourette syndrome is a common hereditary neuropsychiatric disorder consisting of multiple tics and vocal noises. We summarize here clinical aspects of 250 consecutive cases seen over a period of 3 years. The sex ratio was four males to one female, and the mean age of onset was 6.9 years. Only 10% were Jewish, indicating that it is not more prevalent in Ashkenazi Jews. Only 33% had compulsive swearing (coprolalia), indicating that this is not necessary for the diagnosis. The most frequent initial symptoms were rapid eye-blinking, facial grimacing, and throat-clearing. In this series, it was clear that Tourette syndrome is a psychiatric as well as a neurological disorder. Significant discipline problems and/or problems with anger and violence occurred in 61%, and 54% had attention-deficit disorder with hyperactivity. Some degree of exhibitionism was present in 15.9% of males and 6.1% of females. Obsessive-compulsive behavior was seen in 32%. Other than tics and vocal noises, the most common parental complaints were of short temper and everything being a confrontation. There were no significant clinical differences between familial and sporadic cases. Whenever a child presents with a learning disorder, attention-deficit disorder, or significant discipline or emotional problems, the parents should be questioned about the presence of tics or vocal noises in the patient and other family members.

Adolescent↗
PubMed1984

Detection of major gene for Gilles de la Tourette syndrome.

The families of 250 consecutive, unselected patients with Tourette syndrome (TS) were analyzed. If the parents had either motor or vocal tics, but not both, there was an increased risk of both TS and tics in the offspring. The mode of inheritance of the combined tic-Tourette trait was evaluated in both nuclear families and extended pedigrees. Complex segregation analysis was carried out allowing for possible contributions from both a major autosomal locus and multifactorial inheritance of variation in the background of each genotype. The most likely mode of inheritance was a major semidominant gene, Ts, with low heritability of the multifactorial background variation. This was true regardless of assumptions about the prevalence of the disorder. The hypothesis of strict multifactorial inheritance could not be rejected with nuclear family data alone. However, the hypothesis of no major gene effect was rejected using data on 3 generations for any estimate of lifetime risk less than 12 per 1,000 in the general population. A pure recessive major gene effect was also rejected. With a gene frequency of approximately .5%, the penetrance was estimated to be about 94% in abnormal Ts/Ts homozygotes, 50% in Ts/ts heterozygotes, and less than 0.3% in normal ts/ts homozygotes. More than two of every three cases are heterozygotes, and nearly all other cases are phenocopies or new mutations. This is the first demonstration by segregation analysis of a major gene in a human neuropsychiatric disorder with a frequency approaching 1% of the population.

Alleles↗
PubMed1982

A case of familial exhibitionism in Tourette's syndrome successfully treated with haloperidol.

The authors describe a 32-year-old man with Gilles de la Tourette's syndrome whose most severe symptom was exhibitionism. Treatment with low doses of haloperidol eliminated all exhibitionistic urges. This patient's oldest son has multiple tics and his nephew has Tourette's syndrome with mild exhibitionism. The major implications of this case are that 1) all patients with compulsive-type exhibitionism should be carefully questioned about symptoms of Tourette's syndrome and, if positive, be given a trial regimen of haloperidol; 2) some patients with compulsive exhibitionism and no symptoms of Tourette's syndrome have a genetic, neurochemical disorder and respond to haloperidol.

Adult↗