Functional properties of LRRK2 mutations in Taiwanese Parkinson disease.

BACKGROUND/PURPOSE: Leucine-rich repeat kinase 2 (LRRK2) is a large protein encoding multiple functional domains. Mutations within different LRRK2 domains have been considered to be involved in the development of Parkinson disease by different mechanisms. Our previous study found three LRRK2 mutations-p.R767H, p.S885N, and p.R1441H-in Taiwanese patients with Parkinson disease. METHODS: We evaluated the functional properties of LRRK2 p.R767H, p.S885N, and p.R1441H mutations by overexpressing them in human embryonic kidney 293 and neuroblastoma SK-N-SH cells. The common p.G2019S mutation in the kinase domain was included for comparison. RESULTS: In 293 cells, overexpressed p.R1441H-but not p.R767H, p.S885N, or p.G2019-increased GTP binding affinity to prolong the active state. Overexpressed p.R1441H and p.G2019S generated inclusions in 293 cells. In SK-N-SH cells, the α-synuclein was coexpressed with wild type as well as mutated p.R767H, p.S885N, p.R1441H, and p.G2019 LRRK2 proteins. Part of the perinuclear inclusions formed by p.R1441H and p.G2019S were colocalized with α-synuclein. Additionally, p.S885N and p.R1441H mutations caused reduced interaction between LRRK2 and ARHGEF7, a putative guanine nucleotide exchange factor for LRRK2, whereas this interaction was well preserved in p.R767H and p.G2019S mutations. CONCLUSION: Our study suggests that p.R1441H protein facilitates the formation of intracellular inclusions, compromises GTP hydrolysis by increasing its affinity for GTP, and reduces its interaction with ARHGEF7.

Genetic variants ofLRRK2 in Taiwanese Parkinson's disease.

Genetic variants of leucine-rich repeat kinase 2 (LRRK2) were reported to alter the risk for Parkinson's disease (PD). However, the genetic spectrum of LRRK2 variants has not been clearly disclosed yet in Taiwanese population. Herein, we sequenced LRRK2 coding region in 70 Taiwanese early onset PD patients (age at onset ≤ 50), and found six amino acid-changing single nucleotide polymorphisms (SNPs, N551K, R1398H, R1628P, S1647T, G2385R and M2397T), one reported (R1441H) and 2 novel missense (R767H and S885N) mutations. We examined the frequency of identified LRRK2 variants by genotyping 573 Taiwanese patients with PD and 503 age-matched control subjects. The results showed that PD patients demonstrated a higher frequency of G2385R A allele (4.6%) than control subjects (2.1%; odds ratio = 2.27, 95% confidence interval: 1.38-3.88, P = 0.0017). Fewer PD patients (27.7%) carried the 1647T-2397T haplotype as compared with the control subjects (33.0%; odds ratio = 0.80, 95% confidence interval: 0.65-0.97, P = 0.0215). However, the frequency of 1647T-2385R-2397T haplotype (4.3%) in PD patients was still higher than in control subjects (1.9%, odds ratio: 2.15, 95% confidence interval: 1.27-3.78, P = 0.0058). While no additional subject was found to carry R767H and R1441H, one more patient was observed to carry the S885N variant. Our results indicate a robust risk association regarding G2385R and a new possible protective haplotype (1647T-2397T). Gene-environmental interaction and a larger cohort study are warranted to validate our findings. Additionally, two new missense mutations (R767H and S885N) regarding LRRK2 in PD patients were identified. Functional studies are needed to elucidate the effects of these LRRK2 variants on protein function.

[Clinical diagnosis and treatment of acute fatty liver of pregnancy].

OBJECTIVE: To study the clinical diagnosis and treatment of acute fatty liver of pregnancy (AFLP). METHOD: The clinical data of 36 cases of AFLP were reviewed retrospectively, who were treated during Jan 1988- July 2007 in the Department of Obstetrics and Gynecology, Public Health Clinical Center Affiliated to Fu Dan University, Shanghai. RESULTS: All 36 cases were hospitalized in late pregnancy with various clinical symptoms and physical signs. Lab examinations were also performed. In the case of natural delivery, the rate of postpartum hemorrhage, and maternal mortality were 42%, and 50%, and the perinatal mortality and asphyxia in newborns were 50% and 58% respectively. In the case of cesarean section, the rate was 42%, 8%, and 13%, 38% respectively. The comprehensive therapies of termination of pregnancy by cesarean section plus medical supportive treatment can reduce the rate of postpartum hemorrhage, maternal mortality, perinatal mortality, and asphyxia in newborns significantly. Compared with the natural delivery, cesarean section had the higher rate of postpartum hemorrhage and the rate of asphyxia in newborns (P > 0.05), higher rate of maternal mortality and perinatal mortality (P < 0.05). All the death cases occurred in patients who only began to receive treatment 7 days after presentation of the symptoms. Compared with B ultrasonography, of which diagnosis rate of AFLP was 57%, CT had a higher diagnosis rate of 73% (P < 0.05). CONCLUSION: Early diagnosis, termination of pregnancy by cesarean section as soon as possible and a comprehensive therapy are the key to improve the mother and newborn's prognosis.