Clozapine is prescribed to patients with psychosis in whom other treatments have not worked. Research has shown, however, that clozapine may be associated with weight gain and abnormal blood sugar levels in some patients. There is strong evidence to suggest that genetic variation between individuals plays an important role in the development of these side effects in response to the medication. Our research aims to evaluate the effects of two genes and the blood level of clozapine on side-effects such as weight changes and blood sugar levels in patients receiving clozapine treatment. From out-patient clinics in Cwm Taf UHB, the investigators aim to recruit 160 patients who are taking clozapine; collect information/ measurements from recruits relating to size/ weight/ BMI, risk of diabetes and blood samples to measure markers of blood sugar, fat/lipids, clozapine and its breakdown products, blood cells and variants of two specific genes. From this information the investigators will be particularly interested to understand if there is any association between the variation in these two genes with weight gain or changes in blood sugar, in patients taking clozapine.
Study Type
OBSERVATIONAL
Enrollment
160
This is an observational study where the comparative groups will be determined by the genetic variants (SNPs) of subjects and not an intervention, per se.
Cwm Taf University Health Board
Merthyr Tydfil, Wales, United Kingdom
Body-mass index (BMI)
BMI will be calculated by weight (kg)/ height\^2 (m\^2).
Time frame: 12 months
Leptin gene promoter region single nucleotide polymorphisms (SNPs) (rs7799039)
SNPs will be determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis to determine (c.-2548G or c.-2548A) .
Time frame: 12 months
Serotonin 5-HT 2C receptor gene single nucleotide polymorphisms (SNPs) (rs3813929)
SNPs will be determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis to determine (c.-759C or c.-759T) .
Time frame: 12 months
Blood haemoglobin A1c concentration
Haemoglobin A1c concentrations will be determined by ion-exchange HPLC (G8, Tosoh, Amsterdam, Netherlands)
Time frame: 6 months
Waist:hip ratio
Waist:hip ratio will be calculated by waist circumference (cm)/hips circumference (cm)
Time frame: 12 months
Lipid profile
Serum lipid profiles will include total cholesterol, HDL cholesterol, LDL cholesterol and triglyceride. These will be measured by enzymatic colorimetric methods on cobas-Roche analysers (Roche, Burges Hill, UK) except LDL cholesterol, which will be calculated using the Friedewald equation (\[LDL cholesterol\] = \[Total cholesterol\] - (\[Triglyceride\] / 2.2) - \[HDL cholesterol\]
Time frame: 12 months
Clozapine side effects assessment by Clinical Global Impression (CGI) scale
Clinical Global Impression (CGI) scale is a validated tool to assess clozapine side effects (Ref: Guy W, editor. ECDEU Assessment Manual for Psychopharmacology. 1976. Rockville,MD, U.S. Department of Health, Education, and Welfare)
Time frame: 12 months
Clozapine:nor clozapine ratio
Clozapine:nor clozapine ratio is calculated by clozapine (ug/L)/ nor clozapine (ug/L) both measured by high-performance liquid chromatography with diode-array detection.
Time frame: 12 months
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