ABSTRACT
BACKGROUND: Weight gain from atypical antipsychotic use has become a significant problem. Recent reports have liked the -759 polymorphism of the 5HT2C receptor and obesity as well as weight gain from chlorpromazine, risperidone, and clozapine. AIM: To determine associations between weight gain during olanzapine treatment and the -759C/T polymorphism of the 5HT2C receptor gene. METHODS: This study included 42 acutely ill patients with schizophrenia (DSM-IV). Weekly assessments included Brief Psychiatric Rating Scale (BPRS), Scale for Assessment of Negative Symptoms (SANS), and weight measurements. Olanzapine was titrated to a fixed dose (7.5-20 mg/day) for 2-6 weeks. A 24 hr plasma level was obtained at the endpoint visit. Genomic DNA was isolated from a whole blood sample and analyzed for the -759C/T polymorphism of the 5HT2C receptor. RESULTS: A chi-square analysis was conducted comparing the distribution of T and C alleles in subjects grouped as gaining more or less than 5, 7, and 10% of their baseline weight during treatment with olanzapine. A threshold of 10% was found to be significant. The distribution of T alleles was higher in subjects not gaining 10% of more of their body weight compared who did gain significant weight (11/27 (40.7%) vs. 0/15 (100%), chi2 = 11.805, P = 0.0035). CONCLUSIONS: Subjects with a T allele of the 5HT2C receptor -759C/T polymorphism may have a lower incidence of weight gain from olanzapine over a 6 week period compared to those with the C allele. These results need to be replicated.
Subject(s)
Antipsychotic Agents/pharmacology , Benzodiazepines/pharmacology , Polymorphism, Single Nucleotide , Receptor, Serotonin, 5-HT2C/genetics , Weight Gain/genetics , Alleles , Benzodiazepines/blood , Body Weight/drug effects , Body Weight/genetics , Dose-Response Relationship, Drug , Female , Gene Frequency , Genotype , Humans , Male , Olanzapine , Treatment Outcome , Weight Gain/drug effectsABSTRACT
BACKGROUND: In patients with schizophrenia, the percentage of patients with diabetes has been found to be twice that of the normal population. The risk factors for this higher rate are unknown, although dietary, lifestyle, and genetic factors have all been suggested. Recently, a polymorphism (-759C/T) in the serotonin 2C (5HT2C) receptor promoter region has been associated with the development of diabetes in a normal control population, with the frequency of the T allele being higher in subjects without diabetes. AIM: To determine whether the distribution of the -759C/T polymorphism of the 5HT2C receptor is different among patients with schizophrenia and normal controls. METHODS: DNA from 100 patients with schizophrenia and 81 normal controls were analyzed for the 5HT2C receptor -759C/T polymorphism to determine its allelic frequencies in these two groups. RESULTS: Using a chi-squared analysis, no statistical differences in the distribution of C alleles and T alleles were found between the two groups (P=0.2931). CONCLUSIONS: Patients with schizophrenia have a higher risk for developing diabetes than the general population. We did not find a higher distribution of the -759T allele of the 5HT2C receptor in normal controls compared with in patients with schizophrenia. This suggests the higher prevalence of diabetes in schizophrenia is not due to this polymorphism.
Subject(s)
Polymorphism, Single Nucleotide/genetics , Receptor, Serotonin, 5-HT2C/genetics , Schizophrenia/genetics , Cytosine , Female , Genotype , Humans , Iowa , Male , Reference Values , Thymine , White PeopleABSTRACT
Juvenile polyposis (JP) is an autosomal dominant syndrome in which affected patients develop upper- and/or lower-gastrointestinal (GI) polyps. A subset of families with JP have germline mutations in the SMAD4 (MADH4) gene and are at increased risk of GI cancers. To date, six families with JP have been described as having the same SMAD4 deletion (1244-1247delAGAC). The objective of the present study is to determine whether this deletion is a common ancestral mutation or a mutational hotspot. DNA from members of four families with JP, from Iowa, Mississippi, Texas, and Finland, that had this 4-bp deletion was used to genotype 15 simple tandem repeat polymorphism (STRP) markers flanking the SMAD4 gene, including 2 new STRPs within 6.3 and 70.9 kb of the deletion. Haplotypes cosegregating with JP in each family were constructed, and the distances of the closest markers were determined from the draft sequence of the human genome. No common haplotype was observed in these four families with JP. A 14-bp region containing the deletion had four direct repeats and one inverted repeat. Because no common ancestor was suggested by haplotype analysis and the sequence flanking the deletion contains repeats frequently associated with microdeletions, this common SMAD4 deletion in JP most likely represents a mutational hotspot.
