Huntington's disease (HD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene. We have assessed 360 HD individuals from 259 unrelated families and found a highly significant correlation (r = 0.70, p = 10(-7)) between the age of onset and the repeat length, which accounts for approximately 50% of the variation in the age of onset. Significant associations were also found between repeat length and age of death and onset of other clinical features. Sib pair and parent-child analysis revealed that the CAG repeat demonstrates only mild instability. Affected HD siblings had significant correlations for trinucleotide expansion (r = 0.66, p < 0.001) which was not apparent for affected parent-child pairs.

Factors influencing the rate, form, and severity of phenotypic expression among relatives of autistic probands are examined. Family history data on 3095 first- and second-degree relatives and cousins from 149 families with a child with autism and 36 families with a child with Down syndrome are studied. The results provide further evidence of an increased risk among autism relatives for the broadly defined autism phenotype. Of proband characteristics, severity of autism and obstetric optimality were confirmed as being related to familial loading for probands with speech. There was little variation in loading among probands lacking speech. The type of phenotypic profile reported in relatives appeared little influenced by characteristics of the relative or the proband, except for variation by degree of relative, parental status of relative, and perhaps proband's birth optimality score. Phenotypic rates among parents suggested reduced fitness for the severest and more communication-related forms of expression but not for the more mild and social forms of expression. Patterns of expression within the families did not support a simple X-linked nor an imprinted X-linked mode of inheritance. The basis for sex differences in rates of expression is discussed.

Huntington's disease (HD) is associated with expansion of a CAG repeat in a novel gene. We have assessed 21 sporadic cases of HD to investigate sequential events underlying HD. We show the existence of an intermediate allele (IA) in parental alleles of 30-38 CAG repeats in the HD gene which is greater than usually seen in the general population but below the range seen in patients with HD. These IAs are meiotically unstable and in the sporadic cases, expand to the full mutation associated with the phenotype of HD. This expansion has been shown to occur only during transmission through the male germline and is associated with advanced paternal age. These findings suggest that new mutations for HD are more frequent than prior estimates and indicate a previously unrecognized risk of inheriting HD to siblings of sporadic cases of HD and their children.

We have analysed the CAG repeat in the Huntington disease (HD) gene in sperm and blood from 20 unrelated HD patients. Although the CAG repeat displayed significant mosaicism in sperm from all individuals, there were marked differences in the degree of repeat instability. Individuals who had either inherited or transmitted an expanded CAG repeat displayed the highest levels of repeat mosaicism, whereas individuals who had inherited or transmitted a contracted repeat had very limited CAG mosaicism in sperm. A strong association between intergenerational change in CAG allele size and the level of sperm repeat mosaicism was determined (P = 0.019). In contrast, neither blood CAG size nor repeat mosaicism in blood, were significantly associated with intergenerational CAG changes. These data suggest the presence of a cis-acting factor, separate from CAG size, that strongly influences the intergenerational behaviour of the CAG repeat. Additional studies are needed to determine whether analysis of CAG mosaicism in sperm is useful for assessing an individual's risk for transmitting large expansions or contractions to his offspring.

Parents of 144 children with autism spectrum disorders were surveyed regarding their perceptions of and satisfaction with the education their children were receiving. This article focuses on an analysis of the parents' responses to the open-ended questions of this survey. Overall themes that emerged repeatedly across all questions concerned the ability of school personnel to effectively manage children's behavior, teacher education and understanding of the disability, and effective communication and collaboration between parents and school. The implications for future research and practice emerging from these findings are discussed.

As an off-shoot of a study examining the reliability and validity of an adapted version of the Pre-Linguistic Autism Diagnostic Observation Schedule (A-PL-ADOS), 13 individuals with Down syndrome with IQs ranging between 24 and 48 were administered the Autism Diagnostic Interview-Revised (ADI-R) and the A-PL-ADOS, which are well-validated interview and observational diagnostic measures. Three out of 13 met lifetime criteria on the ADI-R, but none of these three showed behavior that met the criterion for autism on the A-PL-ADOS (although two nearly did so). However, two individuals did meet the A-PL-ADOS criterion and showed behavior that fell only just short of meeting lifetime criteria on the ADI-R. Altogether, 5 individuals with Down syndrome may be considered to show an autism spectrum disorder. Of the remaining 8, some showed a few autistic features, and some showed none. The findings raise both methodological and conceptual issues.

This study sought to determine the effects of using music and non-music interventions on the social responsive and avoidant behaviours of a preschool child with autism. A single-subject alternating treatment design was used in which two interventions were presented in a similar fashion except for the addition of music during the music condition. Four phases took place: baseline (Phase A), alternating treatments (Phase B), a second treatment phase (Phase C) using the condition that proved to be more effective in Phase B, and follow-up (Phase D). Data were collected over a total of 12 treatment sessions for various social responsive and avoidant behaviours. Results indicated that the music intervention was more effective than the non-music intervention in increasing all three social responsive behaviours in both Phases B and C. Furthermore, no avoidant behaviours were observed during the music condition. It is suggested that the music condition was more motivating for the participant than the non-music condition, resulting in more social responsive behaviours.

Acute withdrawal from alcohol is associated with a number of unpleasant symptoms that play an important role in preventing recovery and long-term abstinence. Considerable research has focused on the role that neuropeptide systems and the amygdala play in mediating affective symptoms of acute withdrawal, but promising preclinical findings have not translated successfully into the clinic. The rostromedial tegmental nucleus (RMTg) has been implicated in both fear and anxiety. In addition, RMTg neurons exert inhibitory control over midbrain dopamine neurons, the activity of which are suppressed during acute withdrawal. Thus, we hypothesized that the RMTg may play a role in mediating symptoms of acute withdrawal. Using a chronic ethanol vapor exposure paradigm that renders rats physically dependent on ethanol, we observed significant withdrawal-induced enhancement of cFos expression in the RMTg. This was accompanied by a significant increase in somatic symptoms and a decrease in reward sensitivity as measured by intracranial self-stimulation (ICSS). Both measures followed a similar time course to RMTg cFos expression with peak symptom severity occurring 12 h following cessation of ethanol exposure. Heightened anxiety-like behavior was also observed in withdrawn rats at this same time point. RMTg inhibition had no effect on somatic signs of withdrawal or withdrawal-induced changes in reward sensitivity, but significantly attenuated withdrawal-induced anxiety-like behavior. Together, these data demonstrate that the RMTg plays a distinct role in the negative affective state associated with acute withdrawal and may therefore be critically involved in the neurobiological mechanisms that promote relapse during early stages of recovery.