Table 1.

Categories of genetic and environmental contributions in complex diseases. Genetic—Environment Spectrum

Disease	G/E Spectrum	Environmental Driver/Trigger	Genetics
Tay-Sachs [11]	G	None	Hexosaminidase A gene
Iminoglycinuria [12]	G	None	Solute carrier family genes
AMED syndrome [13]	G	None	Alcohol dehydrogenase genes
Prader-Willi (deletion) [14]	G	None	Deletion of genes on Chromosome 15
Prader-Willi (uniparental disomy) [15]	G/E	Intracytoplasmic sperm injection (ICSI)	Maternal uniparental disomy of Chromosome 15
alpha-1 antitrypsin [16]	G/E	Tobacco smoke, chemicals and dust impact severity	SERPINA1 (serine protease inhibitor) gene
spina bifida [17]	G/E	Folate deficiency	Methylenetetrahydrofolate reductase (MTHFR) gene
retinitis pigmentosa [18]	G/E	UV light exposure	> 60 genes identified
myopia [19]	G/E	Near work, outdoor exposure	> 27 genes identified
fetal alcohol syndrome [20]	G/E	Alcohol	None, maternal ability to metabolize alcohol
ricin poisoning [21]	E	Ricin	None

G genetic, G/E genetic and environmental, E environmental