Study Report

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Basic Info

Reference	El-Hadidy, M. A., 2013 PMID: 24276736
Citation	El-Hadidy, M. A., H. M. Abdeen, et al. (2013). "C677T Methylenetetrahydrofolate reductase gene polymorphism in schizophrenia and bipolar disorder." Psychiatr Genet.
Disease Type	Bipolar Disorder & Schizophrenia
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	96 patients diagnosed with schizophrenia and 90 patients diagnosed with BD, 108 healthy controls
SNP/Region/Marker Size	1 polymorphism
Predominant Ethnicity
Population	Egyptian
Gender	44 BD patients, 46 female patients, 68 SZ patients, 28 female patients, 56 male controls, 52 female controls
Age Group	BD: mean age=34.33 (SD=11.13) years, SZ: mean age=35.29 (SD=9.93) years, controls: mean age=34.14 (SD=5.7) years

Detail Info

Sample Diagnosis	DSM IV-TR
Sample Status	404 patients fulfilled the Diagnostic and Statistical Manual, 4th ed. - Text Revision (DSM IV-TR) criteria for either schizophrenia or Mood disorder bipolar I (American Psychiatric Association, 2000). All patients were interviewed using the Mini International Neuropsychiatric Interview. Exclusion criteria were: patients with history of brain injury; neurological disorders; psychiatric disorders due to general medical conditions or substance abuse; or patients related to an individual already included in the study. Patients with any chronic medical diseases or known genetic disease were also excluded. Age of onset at diagnosis of BD: 20 (s.d. 9.05) years, age of onset at diagnosis of SZ: 20.5 (s.d. 7.1) years
Technique	Genotyping of the MTHFR C677Twas performed by PCR and restriction fragment length polymorphism.
Statistical Method	All statistical analyses were performed with the statistical package for the social sciences 20.0 package. The statistically significant difference between patient and control groups was tested using the t-test and analysis of variance test. Statistical significance was defined as a P value less than 0.05. Qualitative variables were expressed as number and percentage. The allele frequencies in the groups of affected patients and controls were compared using a X2-statistic with 1 d.f.
Result Summary	There was significant association of the MTHFR C677T polymorphism with BD and schizophrenia. The T allele was significantly prevalent in the BD and schizophrenia groups compared with the control group. Age at onset was significantly decreased in patients with schizophrenia carrying one copy of the wild C allele or CC genotype but not in patients with BD. In conclusion, the present findings suggest that the MTHFR C677T polymorphism is likely associated with the risk of developing BD and schizophrenia, and influences the age at onset of schizophrenia but not the age at onset of BD.

Genetic factors reported by this study for BD

Other variants reported by this study for BD (count: 1)

Variant Name	Related Gene	Type	Allele Change	Risk Allele	Statistical Values	Author Comments	Result Category
MTHFR C677T	MTHFR	point mutation	C/T		allelic P-value=0.112 for allele C, X²=2.52, OR (CI)=1.871 (0.85-4.09), P-value=0.001 for allele T, X²=11.528, OR (CI)=0.438 (0.27-0.71); genotypic P-value=0.005 for CC, X²=8.039, OR (CI)=2.286 (1.29-4.07)P-value=0.015 for CT, X²=5.967, OR (CI)=0.481 (0.27-0.87), P-value=0.362 for TT, X²=0.830, OR (CI)=0.603 (0.20-1.81)	There is a significant increase in CC genotype distribution ...... There is a significant increase in CC genotype distribution in the control group when compared with the BD and schizophrenia groups. The CT genotype distribution is significantly increased in the BD group versus the control group. The T allele is significantly prevalent in the BD and schizophrenia groups compared with the control group. More...	Positive

Genes reported by this study for BD (count: 1)

Gene	Statistical Values/Author Comments	Result Category
MTHFR	The present findings suggest that the MTHFR C677T polymorphism is likely associated with the risk of...... The present findings suggest that the MTHFR C677T polymorphism is likely associated with the risk of developing BD and schizophrenia, and influences the age at onset of schizophrenia but not the age at onset of BD. More...	Positive

Genetic factors reported by this study for SZ and/or MDD

Other variants reported by this study for SZ/MDD

Disease	Variant Name	Related Gene	Type	Statistical Values	Description	Result Category
SZ	MTHFR C677T	MTHFR	point mutation	allelic P-value<0.05 for allele C, X²=22.171, OR (CI)=4.677 (2.36-9.28), P-value<0.05 for allele T, X²=14.42, OR (CI)=0.412 (0.26-0.65); genotypic P-value=0.016 for CC, X²=5.829, OR (CI)=2.00 (1.14-3.52), P-value=0.826 for CT, X²=0.048, OR (CI)=0.934 (0.51-1.72), P-value=0.001 for TT, X²=10.667, OR (CI)=0.224 (0.09-0.58)	There is a significant increase in CC genotype distribution in the control group when compared with the BD and schizophrenia groups. The TT genotype distribution is significantly increased in the schizophrenia group versus the control group. The T allele is significantly prevalent in the BD and schizophrenia groups compared with the control group. The C allele is prevalent in the control group and its prevalence is statistically significant only when compared with the schizophrenia group.	Positive

Genes reported by this study for SZ/MDD

Disease	Gene	Description	Result Category
SZ	MTHFR	The present findings suggest that the MTHFR C677T polymorphism is likely associated with the risk of developing BD and schizophrenia, and influences the age at onset of schizophrenia but not the age at onset of BD.	Positive