Table 2.

Biologically important MT₁ receptor variants

Amino acid change	Type of variant	Description	Reference
I49N	Missense mutation	Rare variant identified in autism spectrum disorder patients, impaired cell surface expression, melatonin binding, cAMP inhibition and ERK1/1 activation	Chaste et al., 2010
R54W	Missense mutation	Common variant identified in control population without obvious functional defect	Ebisawa et al., 1999
A157V	Missense mutation	Common variant identified in control population without obvious functional defect	Chaste et al., 2010; Ebisawa et al., 1999
G166E	Missense mutation	Common variant identified in control population, impaired cell surface expression, reduced cAMP inhibition and ERK1/2 activation	Chaste et al., 2010
Y170X	Nonsense mutation	Rare variant identified in attention‐deficit hyperactivity disorder (ADHD) patient, premature STOP codon with impaired cell surface expression and cAMP inhibition	Chaste et al., 2011
I212T	Missense mutation	Common variant identified in control population, impaired cell surface expression, cAMP inhibition and reduced ERK1/2 activation	Chaste et al., 2010
A266V	Missense mutation	Common variant identified in control population with reduced ERK1/2 activation	Chaste et al., 2010
K334N	Missense mutation	Rare variant identified in control population with reduced cAMP inhibition	Chaste et al., 2010

Common [minor allelic frequency (MAF) >1%], rare (MAF 0.1–1%) variants.