Clinical features and mutation analysis of LRRK2 gene in patients with autosomal dominant familial Parkinson's disease

Abstract

Objective To investigate the clinical features and LRRK2 gene mutation in patients with autosomal dominant familial Parkinson's disease (PD). Methods The clinical features of 16 autosomal dominant familial PD probands were analyzed in terms of age at onset, onset symptoms, UPDRS scores, response to the levodopa treatment and drug-induced dyskinesia. The LRRK2 gene exons 5,13,31,32,35,37,41 and 48 of 16 probands were sequenced after polymerase chain reaction. The novel mutation was further screened in 24D sporadic PD patients and 214 controls using PCR-RFLP for the genotypo frequency analysis. Results Clinically, most of 16 probands had late-onset age. Resting tremor (9patients, 56. 25%,t=0.558,P=0.679)and bradykinesia (9 patients,56.25%,t=0.369,P=0.454)were common onset symptoms followed by rigidity(6 patients,37.50%,t=1.324,P=0.735)and postural instability(5 patients,31.25%,t=2.369,P=0.956).Majority of them had good response to levedopa treatment and rare occurrence of drug-induced dyskinesia. Among the 16 autosomal dominant familial PD probands,6 variants were identified:c.457 T＞C(Leu153Leu),c.1432 G＞T(Asp478Tyr),c.5457 T＞C(Gly1819Gly),c.7153 G＞A(Gly2385Arg),IVS31+28 T＞G and IVS37+162 T＞C. The c.1432G＞T(Asp478Tyr)variant was a novel mutation and it was not detected in 240 sporadic PD patients and 214 controls. The reported mutations associated with the PD, such as Arg1441 Cys/Gly/His, Arg1514Gln, Tyr1699Cys, Ile2012Thr, Gly2019Ser and Ile2020Thr,were not found in our study. Conclusions The autosomal dominant familial PD patients present with classical symptoms of PD and bear the LRRK2 variantsAsp478Tyr and Gly2385Arg. Key words: Parkinson disease; Protein-serine-threonine kinase; Pedigree; Mutation