High suicidal ideation in persons testing for Huntington's disease.

This study examined the first participants who registered for the Huntington's disease predictive testing program 1990-1995 in Stockholm, Sweden. A psychosocial investigation was performed to evaluate potential effects of the presymptomatic testing. The results showed no significant differences between 13 gene carriers and 21 noncarriers in pretest attitudes, expectations, general well-being, life satisfaction and lifestyle, the need for support, estimated sense of wellbeing or degree of health. However, both groups showed high suicidal ideation and self-injurious behavior. Noncarriers had a very high frequency of attempted suicide, and both groups had similarly pronounced psychiatric dysfunction. Their relatives also had high frequencies of psychiatric diseases, suicide or suicidal attempts. Most of the participants had a desire to meet a psychologist or a social worker. The need for counseling, using a well designed protocol, and the importance of focusing on suicide risk of participants in predictive testing programs is emphasized.

Reactions to predictive testing in Huntington disease: case reports of coping with a new genetic status.

A predictive testing program for Huntington disease has been available in Stockholm, Sweden since October 1990. Psychosocial assessments were performed throughout the testing program to evaluate the impact of the risk situation itself and the effect of predictive testing, and to identify those individuals who were most vulnerable to severe stress and anxiety reactions. All subjects underwent neurological, neuropsychological, and psychiatric examinations. Individuals undergoing predictive testing were assessed twice by a genetic counsellor before receiving their results, and at 10 days (gene carriers only) and then 2, 6, 12, and 24 months after receiving the results. The process of coping with the test results and the psychological adjustment to knowledge about new genetic status have been shown to vary considerably. In this report, we describe the results obtained from two gene carriers and two noncarriers. The four persons chosen represent different ways of coping with the outcome of the test and of integrating knowledge about their genetic status into everyday life. These cases illustrate common themes and recurrent problems often surfacing during the counselling and testing process. The longitudinal evaluations provide information about the impact, adaptation, and long-term effects of living with a new genetic status.

A linkage study of the locus for X-linked Charcot-Marie-Tooth disease.

A large family with Charcot-Marie-Tooth disease, showing a probable X-linked incomplete dominant inheritance, was studied by linkage analysis. Results, obtained by the use of X chromosome specific DNA probes of known regional location, suggest that the disease locus is linked to the DXYS1 locus (z = 2.59 at theta = 0.00) and to the DXS14 locus and, places the disease locus between the DXYS1 locus and the DXS14 locus, near the centromere of the X chromosome. Together with the published data, a distance of 13 cM (z = 6.95) was assessed between the disease locus and the DXYS1 locus.

Genetic regulation of the kinetics of glucose-induced insulin release in man. Studies in families with diabetic and non-diabetic probands.

Insulin release and sensitivity were estimated from glucose and insulin curves obtained at a glucose infusion test performed on altogether 601 subjects belonging to 155 nuclear families. Ascertainment was through one of the parents, and 96 of the probands had diabetes with clinical onset after the age of 30 years, while 59 were healthy subjects. Three variables obtained by a computer model were analysed, i.e. the glucose regulation of insulin release by a direct stimulatory event (KI) and time-dependent modulatory events (KP) as well as insulin sensitivity (KG). Complex segregation analysis revealed that the variables are genetically regulated, but there was no evidence for a major locus. The children of the diabetics did not differ from those of the non-diabetics as far as insulin release is concerned.

Evidence for an autosomal recessive gene regulating the persistence of the insulin response to glucose in man.

The significance of genetic factors for insulin release after glucose infusion was studied in 155 nuclear families of which 59 were control families and 96 had been ascertained through a parent with onset of diabetes after 30 years of age. Fasting insulin and glucose as well as three principal components of the insulin and glucose curves were submitted to path analysis and complex segregation analysis. The three principal components were considered to reflect the magnitude, the degree of response and the persistence of the curves. The genetic heritability of the insulin variables varied between 0.47-0.93 and that of the glucose variables between 0.20-0.54. There were considerable intergenerational differences in the genetic heritability for the persistence of the glucose curve and for the degree of response and persistence of the insulin curve. The cultural heritability was found to be of minor importance, while the non-transmitted sibling environment was large. There was significant evidence for a major locus for the persistence of the insulin curve. The best fit was for a completely recessive autosomal gene with the gene frequency 0.21. The phenotype distribution of this variable showed significant kurtosis which could simulate a major locus. However, the significant evidence for such a locus remained after an analysis using partial quantitation. The diabetics were significantly different from the non-diabetics for all the variables studied, but a complete discrimination between the diabetics and non-diabetics could not be obtained. There was no significant difference between the children of the diabetics and non-diabetics for any of the variables studied.