OBJECTIVE: To follow the clinical course of patients with the mitochondrial DNA mutation 3243A>G for 3 years. METHODS: Thirty-three adult patients with the 3243A>G mutation entered a 3-year follow-up study. They were clinically evaluated annually, audiometry was performed, and samples were drawn for the analysis of blood chemistry and mutation heteroplasmy in leukocytes. Holter recording was performed three times during the follow-up and echocardiography, neuropsychological assessment, and quantitative EEG and brain imaging conducted at entry and after 3 years. RESULTS: The incidence of new neurologic events was low during the 3-year follow-up. Sensorineural hearing impairment (SNHI) progressed, left ventricular wall thickness increased, mean alpha frequency in the occipital and parietal regions decreased, and the severity of disease index (modified Rankin score) progressed significantly. The rate of SNHI progression correlated with mutation heteroplasmy in muscle. The increase in left ventricular wall thickness was seen almost exclusively in diabetic patients. Seven patients died during the follow-up, and they were generally more severely affected than those who survived. CONCLUSIONS: Significant changes in the severity of disease, sensorineural hearing impairment, left ventricular hypertrophy, and quantitative EEG were seen in adult patients with 3243A>G during the 3-year follow-up.
Comment In: Neurology. 2007 Jan 9;68(2):163-417210904
OBJECTIVE--To study the prevalence of family history of diabetes, overweight, and glucose intolerance in a defined general population, and the associations between these variables and others involved in the so-called metabolic syndrome (blood pressure, obesity, serum lipids). DESIGN--An oral glucose tolerance test (OGTT) was done on all participants in a population study who reported a family history of diabetes or had a body mass index (BMI) > or = 27. SETTING AND PARTICIPANTS--A population study of men aged 33-42 was carried out at Habo in southwestern Sweden (participation rate 86.1%). An OGTT was done on 170 men who fulfilled the criteria stated above. RESULTS--Overweight was a risk factor for impaired glucose tolerance and was more strongly associated with this state than was a family history of diabetes. Glucose intolerance was also associated with increased blood glucose concentration during the OGTT and with other metabolic disturbances such as increased serum lipids, increased blood pressure, and physical inactivity. CONCLUSIONS--The combination of overweight and impaired glucose tolerance is already common at a rather young age in men and is often combined with impairment of arterial blood pressure and serum lipids. The results indicate that it is urgent to start preventive measures early in life.
A single-gene rodent mutation (diabetes) and a quantitative trait locus (dietary obese 1) mapped to the mid portion of mouse chromosome 4 have been related to obesity and/or insulin levels. Synteny relationships place their putative human homologs on 1p31 and 1p35-p31, respectively. In 137 sibships of adult brothers and sisters from the Québec Family Study, genetic linkages between seven microsatellite markers from 1p32-p22 and various obesity- and diabetes-related quantitative phenotypes were examined using single locus sibpair linkage analysis. Suggestive linkages were observed between markers D1S476 and body mass index (p = 0.05), fat mass (p = 0.02), the sum of six skinfolds (p = 0.02), the insulin area after an oral glucose tolerance test (p = 0.02), and between the neighboring marker D1S200 and body mass index (p = 0.03), and fat mass (p = 0.009). Suggestive linkages were also observed between the more telomeric markers D1S193 and body mass index (p = 0.03), and between the neighboring marker D1S197 and fasting insulin level (p = 0.05). No linkage was observed with the trunk to extremity skinfolds ratio. These linkages suggest that human homologs of the mouse diabetes or dietary obese 1 and/or other genes in this interval on chromosome 1 play a role in the regulation of body mass, body composition, and insulin levels, but not of subcutaneous fat distribution.