Validation of differential GDAP1 DNA methylation in alcohol dependence and its potential function as a biomarker for disease severity and therapy outcome

Figures & data

Table 1. Characterization of patients and control individuals. Errors are given as standard deviation (SD). Amount of drinks is the standardized unit originating from the AUDIT questionnaire.

	Control individuals	Patients	P-value
Total N	37	49
Age (years)	47 ± 12.32	49 ± 10.47	0.30
Smokers (% of total)	29 (78%)	38 (79%)	0.93
Cigarettes smoked daily	16 ± 10.99	20 ± 10.93	0.18
Days since last drink		2.9 ± 6.9
Amount of drinks consumed daily one week before hospital admission		17 ± 13.1
Years of alcohol dependency		12.3 ± 9.9

Figure 1. DNA methylation levels at (A) site 1 / cg23779890, (B) site 2 and (C) site 3 for control individuals, patients at T1 and patients at T2. Significant differences are indicated with * (P ≤ 0.05) and *** (P ≤ 0.001).

Table 2. DNA methylation levels, AUDIT and GSI scores for control individuals vs. patients at T1. DNA Methylation level errors are given as standard error of the mean (SE), questionnaire score errors are given as standard deviation (SD).

	Control individuals	Patients at T1	P-value
Site 1 (cg23779890)	7.8 ± 0.2	6.6 ± 0.3	0.001
Site 2	4.0 ± 0.1	3.6 ± 0.1	0.015
Site 3	2.1 ± 0.1	1.9 ± 0.1	0.012
Mean DNA methylation (sites 1 – 3)	4.6 ± 0.1	4.0 ± 0.2	0.001
AUDIT score	4.9 ± 3.7	25.1 ± 6.1	5.1E-15
GSI score	0.16 ± 0.13	0.78 ± 0.54	1.7E-10

Table 3. DNA methylation levels, OCDS and GSI scores for patients at T1 vs. patients at T2. DNA Methylation level errors are given as standard error of the mean (SE), questionnaire score errors are given as standard deviation (SD).

	Patients at T1	Patients at T2	P-value
Site 1 (cg23779890)	6.6 ± 0.3	7.3 ± 0.3	0.001
Site 2	3.6 ± 0.1	3.8 ± 0.1	0.033
Site 3	1.9 ± 0.1	2.0 ± 0.1	0.001
Mean DNA methylation(sites 1 – 3)	4.0 ± 0.2	4.4 ± 0.2	0.001
OCDS score	3.93 ± 1.32	2.71 ± 0.96	2.1E-5
GSI score	0.78 ± 0.54	0.48 ± 0.49	0.008