Alternative hypotheses on the inheritance of Tourette syndrome.
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Genetic Linkage↗
Biomedical subjects
B G Comings
Publications and source records attributed to B G Comings.
The dopamine D2 receptor locus as a modifying gene in neuropsychiatric disorders.
OBJECTIVE: --The A1 allele of the Taq I polymorphism of the dopamine D2 receptor (DRD2) gene has been earlier reported to occur in 69% of alcoholics, compared with 20% of controls. Other research has reported no significant difference in the prevalence of the A1 allele in alcoholics vs controls and no evidence that the DRD2 gene was linked to alcoholism. We hypothesized that these seemingly conflicting results might be because increases in the prevalence of the A1 allele may not be specific to alcoholism. Thus, we examined other disorders frequently associated with alcoholism or those believed to involve defects in dopaminergic neurotransmission. DESIGN: --Case comparison study. To minimize the effect of racial differences in gene frequencies, the study was restricted to non-Hispanic whites. SETTING: --Ambulatory and hospitalized patients. RESULTS: --Among all known controls (n = 314), 77 (24.5%) carried the A1 allele. Of the 69 controls known not to be alcoholics, 10 (14.5%) carried the A1 allele. The prevalence of the A1 allele was significantly increased in patients with Tourette's syndrome (44.9%, n = 147), attention deficit hyperactivity disorder (46.2%, n = 104), autism (54.5%, n = 33), alcoholism (42.3%, n = 104), and posttraumatic stress disorder (45.7%, n = 35). After correction for multiple comparisons (requiring P less than .0009 for significance), all remained significant except posttraumatic stress disorder. The prevalence of the A1 allele was not significantly increased in patients with depression, panic attacks, Parkinson's disease, or obesity. The prevalence of the A1 allele in drug addiction and schizophrenia was only significant when compared with that of controls who were not alcoholics, and no correction was made for multiple comparisons. CONCLUSION: --These results suggest the A1 allele of the DRD2 gene is associated with a number of behavior disorders in which it may act as a modifying gene rather than as the primary etiological agent.
Alcoholism↗
Clinical and genetic relationships between autism-pervasive developmental disorder and Tourette syndrome: a study of 19 cases.
Children with autism or pervasive developmental disorder (PDD) and Tourette syndrome (TS) share a number of symptoms. Forty-one cases have been reported in which PDD patients subsequently developed TS. We term this PDD----TS. We describe an additional 16 such patients plus 3 families where a close relative of a TS proband had autism. There was a high frequency of alcoholism, drug abuse, obsessive-compulsive, and other behavior disorders in the relatives of these patients. This frequency was virtually identical to that observed in relatives of individuals with TS only. We suggest there is an intimate genetic, neuropathologic relatedness between some cases of PDD and TS. Many observations have led us to suggest that the genetic defect in TS may be a mutation of tryptophan oxygenase and that TS is inherited as a semidominant semirecessive trait, i.e., homozygosity for a common gene which shows some expression in the heterozygous state. We propose that some types of PDD are inherited in the same fashion and by the same gene. This would explain the similarity of symptoms, frequent evolution of PDD into TS, the apparent recessive inheritance of PDD despite no increase in consanguinity, the high frequency of behavior problems in the relatives of PDD----TS patients and the serotonin abnormalities.
Adolescent↗
The clonidine patch and behavior problems.
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Administration, Cutaneous↗
An epidemiologic study of Tourette's syndrome in a single school district.
To evaluate the frequency of Gilles de la Tourette's syndrome (TS) in children, 3034 students in three schools in a single school district in greater Los Angeles were monitored frequently over a 2-year period by a school psychologist thoroughly familiar with the symptoms of the disorder. A portion of the cases were also evaluated in a TS clinic. A total of 14 males fulfilled the Tourette Syndrome Association research criteria for definite TS. When corrected for the number of students in special education classes in the monitored schools, the frequency of definite TS in males was 1 in 152. An additional 7 males who differed only in that they were not observed for a full year were termed definite TS less than 1 year. When the two groups were combined, the frequency of definite TS was 1 in 95 for males and 1 in 759 for females. These figures do not include an additional 10 males diagnosed as having definite transient tic disorder, 2 males diagnosed as having probable TS, and 10 males diagnosed as having possible TS. In addition to tics, most of these children had problems with attention span, obsessive compulsive behavior, and learning and/or conduct disorders. Seventy percent of the students with definite TS or definite TS less than 1 year were in special education classes. Twelve percent of the children in special education classes had definite TS or definite TS less than 1 year, and 28% were in one of the diagnostic categories of definite, probable, or possible. All of the 10 definite TS patients that were seen in the clinic had attention-deficit hyperactivity disorder.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
A controlled family history study of Tourette's syndrome, I: Attention-deficit hyperactivity disorder and learning disorders.
Gilles de la Tourette's syndrome (TS) is a common, hereditary neuropsychiatric disorder. While its diagnostic feature is the presence of suppressible motor and vocal tics, a wide range of impulsive, compulsive, attentional, learning, mood, and anxiety disorders are also present in many patients. To determine if attentional and learning problems are part of the expression of the Gts gene (or genes), the authors analyzed family histories of 130 TS probands with 1851 relatives and 25 control probands with 541 relatives--a total of 2392 relatives. The frequency of attention-deficit hyperactivity disorder (ADHD) or learning disorders was significantly increased in the relatives of the TS probands. The data on first-degree relatives suggest that when the Gts gene is expressed in this form, in two thirds of the cases tics are also present and in one third they are not. These observations are consistent with the proposal that ADHD and learning disorders form an integral part of the expression of the Gts gene or genes.
Adolescent↗
A controlled family history study of Tourette's syndrome, II: Alcoholism, drug abuse, and obesity.
The behaviors associated with Gilles de la Tourette's syndrome (TS), including impulsive, compulsive, attentional, learning, conduct, and mood disorders, have often been described as substrates for the development of alcoholism and/or drug abuse. As the authors' experience with TS pedigrees indicated that alcoholism and/or drug abuse were common in relatives of TS probands, they examined, by the family history technique, 1750 relatives over 14 years of age in 130 TS proband and 25 control families. Significant, life-disrupting problems with alcoholism and/or drug abuse were present in 14.5% of the relatives of TS probands compared with 4.4% of the control relatives (p less than .00001). Among parents of TS probands, the ratio of affected fathers to mothers was 2:1. Marked obesity (greater than 100 lb) was present in 10.8% of the mothers and 3.2% of all relatives of TS probands compared with 0.8% of all control relatives (p = .01). In parents of TS probands, the ratio of marked obesity in fathers to that in mothers was 1:4.5. When the categories of alcoholism and/or drug abuse and marked obesity were combined, 17.4% of all relatives of TS probands were affected compared with 4.6% of all control relatives (p less than .0001) and the ratio of fathers to mothers with these disorders was 1.1:1. Among all relatives of TS probands, 20.8% of those with tics and 17.4% of those without tics had problems with alcoholism and/or drug abuse or obesity or both. This finding suggests that when the Gts gene(s) is expressed in this form it is about equally likely to occur in persons with and persons without tics. The similarities between TS and early onset, male predominant, Type II alcoholism suggest that in some cases, alcoholism and/or drug abuse in males and severe obesity in females are related, genetically controlled, compulsive behaviors.
Adolescent↗
A controlled family history study of Tourette's syndrome, III: Affective and other disorders.
In a family history study, the frequency of affective disorders was significantly higher for all relatives of Gilles de la Tourette's syndrome (TS) patients than for all relatives of controls. Among the relatives of TS patients, the presence of any behavior disorder was significantly more frequent for first-, second-, and third-degree relatives and total relatives. Among all relatives, 30.6% of the relatives of TS patients versus 6.1% of control relatives (p less than .0001) had some behavior disorder. Studies of first-degree relatives suggest that among those individuals expressing the Gts gene as some type of behavioral problem, about half have tics and half do not. These observations suggest that in addition to tics that Gts gene(s) can be expressed as a spectrum of behavioral disorders.
Age Factors↗
Hypothesis: homozygosity in Tourette syndrome.
We review evidence suggesting that many individuals with Tourette syndrome (TS) may be homozygous for a "Tourette syndrome" gene. This is based on experience with pedigrees on 1,200 TS families, comparison of the occurrence of tics or associated behaviors such as obsessive-compulsive behavior, panic attacks, attention deficit hyperactivity disorder, and/or severe alcohol or drug abuse, on both the maternal and paternal side in 170 TS families compared to control families, biochemical studies of blood serotonin and tryptophan levels, and other evidence. These observations suggest the inheritance in TS may be best described as semi-dominant, semi-recessive. Some of the implications of this proposal are discussed.
Adult↗
Tourette's syndrome and attention deficit disorder with hyperactivity.
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Attention Deficit Disorder with Hyperactivity↗
Hereditary agoraphobia and obsessive-compulsive behaviour in relatives of patients with Gilles de la Tourette's syndrome.
We present 11 pedigrees in which a propositus with Gilles de la Tourette's syndrome had first or second-degree relatives with obsessive-compulsive behaviour or agoraphobia with panic attacks, but only partially expressed the TS gene (i.e. had only motor tics or vocal tics, or neither). Of 90 females over the age of 18 presenting with TS, or with motor or vocal tics alone, nine had severe agoraphobia with panic attacks. There may be genetic subtypes of both obsessive-compulsive disorder and agoraphobia with panic attacks that are due to partial expression of the TS gene.
Adolescent↗
A controlled study of Tourette syndrome. I. Attention-deficit disorder, learning disorders, and school problems.
Tourette syndrome (TS) is a common, hereditary, neurobehavioral disorder of childhood. To determine the frequency of various behavioral manifestations, we have compared 47 random normal controls to 246 patients with TS, 17 with attention-deficit disorder (ADD), and 15 with ADD secondary to a TS gene (ADD 2(0) TS). All subjects were examined prospectively with a 425-item questionnaire based on the Diagnostic Interview Schedule and the Diagnostic and Statistical Manual of Mental Disorders (DSM III). The TS patients were divided into grade 1 (too mild to treat [17.5%]), grade 2 (requiring treatment [58.9%]), and grade 3 (severe [23.6%]). Patients in all three grades of TS were significantly different from controls for DSM III symptoms of inattention, impulsivity, and hyperactivity. Sixty-two percent of TS patients had ADD, compared with 6.3% of controls; and 48.8% had ADD with hyperactivity (ADDH), compared with 4.2% of controls. In the majority of TS patients, the natural history of the disease was to start with ADDH and 2.4 years later develop motor and vocal tics. Among TS patients, 39% had previously received medication for ADDH or behavior problems, compared with 2% of the controls. Although stimulants can occasionally exacerbate tics, there was no evidence that stimulants cause TS and they are often a valuable adjunct to the treatment of TS. It is estimated that 10%-30% of ADDH is due to or associated with the presence of a TS gene. TS patients had a significantly increased frequency of (1) attending classes for the educationally handicapped, (2) placement in classes for the severely emotionally disturbed, (3) attending any special classes, (4) severe test anxiety, (5) stuttering, (6) letter, number, or word reversal, (7) reading very slowly, and (8) poor retention of material read. A reading-problem score (dyslexia) greater than or equal to 3 was present in 26.8% of TS patients, compared with 4.2% of controls. Number reversal, word reversal, and poor retention were significant even for the TS patients with tics too mild to treat. The multiple ways in which TS impacts school performance, as well as potential remedies, are discussed.
Adolescent↗
A controlled study of Tourette syndrome. II. Conduct.
To assess conduct in Tourette syndrome (TS), 47 controls, 246 TS patients, 17 attention-deficit-disorder (ADD), and 15 ADD patients with minor tics or a family history of TS (ADD 2(0) TS) were compared for the following behaviors: running away from home, lying, stealing, starting fires, vandalism, being in trouble with the law, fighting, shouting at parents or peers, attacking others, lack of respect for adults, short temper, hurting animals, feeling full of hate, being unable to stop fighting, and problems with drugs and alcohol. With the exception of running away from home and being in trouble with the law, TS patients were significantly different from controls in all other behaviors. When the components were combined for a total conduct score, only one (2.1%) of the controls had a score greater than 13, and he had TS. By contrast, 35% of the TS patients had scores greater than 13 (P less than .0005). The correlation coefficient between the total conduct score and ADD score was .48. Although the presence of ADD was an important factor in determining conduct in TS, other factors such as depression and compulsive behavior also played a contributing role. There was little correlation between the total conduct score and the number of tics. It is estimated that among non-economically disadvantaged children, 10%-30% of conduct disorder may be due to the presence of a TS gene.
Adolescent↗
A controlled study of Tourette syndrome. III. Phobias and panic attacks.
Comparison was made of the frequency of phobias and panic attacks in normal controls and in patients with Tourette syndrome (TS), attention-deficit disorder (ADD), and ADD secondary to a TS gene. For phobias the most significant difference between controls and TS patients was with respect to fear of public transportation (P = .002), followed by fear of being alone (P = .009), fear of being in a crowd (P = .01), fear of being in water (P = .025), fear of animals (P = .04), fear of public speaking (P = .05), and other fears (P = .05). Only 8.5% of controls had more than three simple phobias and none had more than five, whereas 26% of TS patients had more than three (P = .008) and some had as many as 13. As opposed to 19% of TS patients, none of the controls had phobias that interfered with their life (P = .001). Among female TS patients 55.1% had 3-13 phobias, compared with 8.7% of the female controls (P less than .0005). There was no correlation between the ADD score and the number of phobias (r = -.010) and little correlation with the total number of tics (r = .14). Panic attacks were present in 8.3% of the controls and 33% of the TS patients (P = .0008). This frequency increased to 55.2% (P less than .0005) for grade 3 (severe) TS patients. None of the controls, 15.9% of all TS patients (P = .002), and 31% of grade 3 TS patients (P less than .0005) had more than three panic attacks in 1 wk. Total panic-symptom score (12 possible symptoms) was significantly greater than that in the controls in all grades of TS. The presence or absence of ADD had little effect on the total panic-symptom score, but the presence of ADD resulted in a significantly lower average age at onset of panic attacks (8.8 years) compared with those TS patients without ADD (15.4 years) (P = .03). These observations indicate that phobias and panic attacks are a significant part of the symptomatology of TS and provide the first clear indication that phobias and panic attacks can be due to the presence of a major gene.
Adolescent↗
A controlled study of Tourette syndrome. IV. Obsessions, compulsions, and schizoid behaviors.
To determine the frequency of obsessive, compulsive, and schizoid behaviors in Tourette syndrome (TS), we prospectively questioned 246 patients with TS, 17 with attention-deficit disorder (ADD), 15 with ADD due to a TS gene, and 47 random controls. The comparative frequency of obsessive, compulsive, and repetitive behaviors--such as obsessive unpleasant thoughts, obsessive silly thoughts, echolalia, palilalia, touching things excessively, touching things a specific number of times, touching others excessively, sexual touching, biting or hurting oneself, head banging, rocking, mimicking others, counting things, and occasional or frequent public exhibitionism--were significantly more common in TS patients than in controls. The frequency of each of these was much higher for grade 3 (severe) TS. Most of these behaviors also occurred significantly more often in individuals with ADD or in individuals with ADD secondary to TS (ADD 2(0) TS). When these features were combined into an obsessive-compulsive score, 45.4% of TS patients had a score of 4-15, whereas 8.5% of controls had a score of 4 or 5. These results indicate that obsessive-compulsive behaviors are an integral part of the expression of the TS gene and can be inherited as an autosomal dominant trait. Schizoid symptoms, such as thinking that people were watching them or plotting against them, were significantly more common in TS patients than in controls. Auditory hallucinations of hearing voices were present in 14.6% of TS patients, compared with 2.1% of controls (P = .02). These symptoms were absent in ADD patients but present in ADD 2(0) TS patients. These voices were often blamed for telling them to do bad things and were frequently identified with the devil. None of the controls had a total schizoid behavior score greater than 3, whereas 10.9% of the TS patients had scores of 4-10 (P = .02). This frequency increased to 20.6% in the grade 3 TS patients. These quantitative results confirm our clinical impression that some TS patients have paranoid ideations, often feel that people are out to get them, and hear voices.
Adolescent↗
A controlled study of Tourette syndrome. V. Depression and mania.
To evaluate the role of depression and mania in Tourette syndrome (TS), we have examined 246 TS patients, 17 attention-deficit disorder (ADD) patients, 15 patients with ADD associated with TS, and 47 controls, using (1) the standardized National Institutes of Mental Health Diagnostic Interview Schedule questions for a life history of major depression and/or mania and (2) a modified Beck depression score for evaluation of depression at the time of the examination. The results were combined into depression, Beck, and mania scores. Among the controls, 2.1% had a depression score greater than 9, and none had a score greater than 10. Among the TS patients, 22.9% had a score greater than 9 and the scores ranged up to the maximum of 18 (P less than .0005). None of the pure ADD patients had a score greater than 6, whereas 20% of the ADD-secondary-to-TS (ADD 2(0) TS) patients had scores greater than or equal to 9. Among grade 3 TS patients, 46.6% had scores greater than or equal to 9. There were no differences in the frequency of depression in the TS patients with or without ADD. Comparable results were obtained for the Beck depression score, except that the percent with a score greater than or equal to 8 was higher for the TS patients with ADD (23.7%) than for those without ADD (9.3%). There was a good correlation between the depression score and the Beck score (r = .63), but no correlation between the ADD-with-hyperactivity (ADDH) score and either the depression score (r = .086) or the Beck score (r = .077). Among the controls, none had a mania score greater than or equal to 4, compared with 19.1% of the total TS patients (P = less than .0005), 11.8% of the ADD patients (P = .002), and 26.6% of the ADD 2(0) TS patients (P = .0005). Although some of the mania questions would be expected to be answered positively by ADDH patients, the correlation coefficient between the ADDH scores and the mania scores was only moderate (r = .29), whereas the correlation with the depression score was much higher (r = .63). There was minimal correlation between the number of tics and either the depression score (r = .267) or the Beck score (r = .193). We conclude that depression and manic-depressive symptoms are common in TS patients and are an integral part of the disorder rather than being secondary to motor or vocal tics.
Adolescent↗
A controlled study of Tourette syndrome. VI. Early development, sleep problems, allergies, and handedness.
Developmental milestones, problems with bladder and bowel control, sleep disturbances, allergies, and handedness were compared in 247 consecutive Tourette syndrome (TS) patients, 17 patients with attention-deficit disorder (ADD), 15 patients with ADD secondary to TS (ADD 2(0) TS), and 47 random controls. There were no significant differences in age of first talking or walking. By contrast, there were significant differences in problems with bladder and bowel control between TS patients and controls, as measured by age of first toilet training, age of last bed-wetting, frequency of enuresis, and age that bowel control was achieved. Sleep problems were pervasive in TS patients, with a significantly increased frequency of sleepwalking, night terrors, trouble getting to sleep, early awakening, and inability to take afternoon naps as a young child. In all diagnostic categories, including mild (grade 1) TS patients, a total sleep-problem score was significantly greater than that in controls. The sleep disorders and other TS symptoms are consistent with TS as a disorder of disinhibition of the limbic system. Allergies and left-handedness have been evoked as contributing to or being associated with ADD and learning disorders. There were no significant differences in the frequency of allergies or left-handedness in TS patients compared with that in controls. We conclude that when there is a clearly defined genetic cause of ADD and learning disorders, it is not associated with an increased frequency of allergies or left-handedness.
Adolescent↗
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↗