MTHFR Gene Polymorphism and Age of Onset of Schizophrenia and Bipolar Disorder

Table 3

Mean age at onset and results of ANOVA test for genotype and allele frequency of MTHFR C677T in the bipolar and schizophrenia groups.

Diagnosis

Genotype

Age at onset (Years)

𝐹

𝑃 value

Scheffe test (𝑃 value)

Allele frequencies

Age at onset (Years)

𝑡

𝑃 value

Mean ± SD

CC-CT

CC-TT

CT-TT

Mean ± SD

Bipolar disorder; (𝑁 = 134)

CC

23.65 ± 7.99

5.876

0.004

0.004

0.145

0.946

C

Present

21.43 ± 8.6

2.176

0.032

CT

18.51 ± 8.7

Absent

19.22 ± 4.5

TT

19.22 ± 4.6

T

Present; Absent

18.75 ± 7.5; 23.65 ± 7.94

−4.445

0.000

Schizophrenia; (𝑁 = 136)

CC

19.96 ± 5.37

10.74

0.000*

−0.06

0.01

0.000

C

Present

20.74 ± 6.09

5.42

0.00

CT

23.00 ± 7.5

Absent

14.67 ± 1.5

TT

14.67 ± 1.5

T

Present; Absent

19.21 ± 7.0; 19.96 ± 5.4

0.79

0.431

SD: standard deviation. *Significance (𝑃 < 0.05).