Table 1.

Summary of OX₁ and OX₂ orexin receptor variants: investigations in disease.

OX1 aa	Corresponding aa in OX2	Location	SNP (or other access code)	Numbering/peyron	Numbering/olafsdottir	Findings	References
167 Gly/Ser	Ile	TM4	rs144603792		652 G/A	Not linked with narcolepsy	Olafsdottir et al., 2001
265 Leu/Met	a	IC3		793 C/A		Not linked with narcolepsy	Peyron et al., 2000
279 Arg/Gln	a	IC3	rs7516785		989 G/A	Not linked with narcolepsy	Olafsdottir et al., 2001
280 Gly/Ala	a	IC3	NP_001516 (C), AF041243 (G)
281 Arg/His	a	IC3	rs41439244	842 G/A	995 G/A	Not linked with narcolepsy	Peyron et al., 2000; Olafsdottir et al., 2001
408 Ile/Val	a	C-terminus	rs2271933	1222 G/A	1375 G/A	Not linked with narcolepsy	Peyron et al., 2000; Olafsdottir et al., 2001
						A allele associated with 1.4-fold risk of migraine	Rainero et al., 2011b
						1.6-fold increased risk of major mood disorders	Rainero et al., 2011a
						Association with polydipsia–hyponatremia in schizophrenia possible	Meerabux et al., 2005; Fukunaka et al., 2007
						No allele associations in panic disorder	Annerbrink et al., 2011
OX2 aa	Corresponding aa in OX1	Location	SNP	Numbering/peyron	Numbering/olafsdottir	Findings	References
10 Pro/Ser	Pro	N-terminus	rs41271310	28 C/T	352 C/T	Not linked with narcolepsy	Peyron et al., 2000; Olafsdottir et al., 2001; Thompson et al., 2004
11 Pro/Thr	a	N-terminus	rs41271312	31 C/A	355 C/A	Not linked with narcolepsy	Peyron et al., 2000; Olafsdottir et al., 2001
						Tourette syndrome/ADHD/sleep disorder 1.6 and 2.7-fold shifts in EC50 for orexin-A and -B	Thompson et al., 2004
193 Cys/Ser	a	TM4		577 T/A		Not linked with narcolepsy	Peyron et al., 2000
293 Ile/Val	a	IC3			1201 G/A	Not linked with narcolepsy	Olafsdottir et al., 2001
308 Ile/Val	Val	TM6	rs265334	922 G/A	1246 G/A	Not linked with narcolepsy	Peyron et al., 2000; Olafsdottir et al., 2001
						Ile variant associated with panic disorder in female patients	Annerbrink et al., 2011
						Migraine not associated. Association with CH found in some but not in all studies	Baumber et al., 2006; Schürks et al., 2006; Rainero et al., 2008
						Does not affect migraine drug response	Schürks et al., 2007a
401Thr/Ile	a	C-terminus		1202 C/T		Not linked with narcolepsy	Peyron et al., 2000

aa, amino acid; IC, intracellular loop; SNP, single nucleotide polymorphism; TM, transmebrane helix.

^aThe corresponding amino acids can be defined with certainty only for TM regions.