Table 1.

Simplified overview of some of the genes implicated in Parkinson’s disease

Gene	Nomenclature (locus)	Known mutations/variants	Clinical features	Penetrance by age 80*
Autosomal dominant forms of PD
SNCA	PARK1 and PARK 4	Missense mutations: A53T, A30P, E46K, G50D Duplications and triplications	YOPD, atypical and severe phenotypes depending on the specific mutation (i.e. triplications give a more severe phenotype)	probably high, > 90% for A53T, unknown for others
LRRK2	PARK8	G2019S: a missense mutation which is a frequent determinant of familiar and sporadic PD R1441G, Y1699C, I2020T	Classical (late-onset) PD	G2019S: 25–74%
GBA1	–	Mutations in GBA1 gene (NM_000157.3), also associated with Gaucher disease: N370S, S2716, L444P GBA1 variants (not associated with Gaucher disease)	Classical PD but with a slightly earlier onset age, severe motor impairment and higher prevalence of dementia and RBD	N370S, S2716: low risk, 7.6% L444P: high risk, 11–29.7%
Autosomal recessive forms of PD
Parkin	PARK2		YOPD	100%
PINK1	PARK6		YOPD	100%
DJ-1	PARK7		YOPD	100%

PD  Parkinson’s disease, SNCA  α-synuclein, LRRK2  leucine-rich repeat kinase 2, GBA  glucocerebrosidase, RBD  REM sleep behavior disorder, YOPD  young onset PD, PINK1  PTEN induced putative kinase 1

*As determined by Heinzel et al. (2019)