Lrrk2 p.Q1111H substitution and Parkinson's disease in Latin America

Mutations in the LRRK2 gene are the most common genetic cause of Parkinson's disease, with frequencies displaying a high degree of population-specificity. Although more than 100 coding substitutions have been identified, only seven have been proven to be highly penetrant pathogenic mutations. Studies however are lacking in non-white populations. Recently, Lrrk2 p.Q1111H (rs78365431) was identified in two affected Hispanic brothers and absent in 386 non-Hispanic white healthy controls. We therefore screened this variant in 1460 individuals (1150 PD patients and 310 healthy controls) from 4 Latin American countries (Peru, Chile, Uruguay and Argentina). In our case-control series from Peru and Chile we observed an increased frequency of Lrrk2 p.Q1111H in patients (7.9%) compared to controls (5.4%) although the difference did not reach significance (OR 1.38; p = 0.10). In addition, the frequency of Lrrk2 p.Q1111H varied greatly between populations and further screening in a set of pure Amerindian and pure Spanish controls suggested that this variant likely originated in an Amerindian population. Further studies in other Latin American populations are warranted to assess its role as a risk factor for Parkinson's disease. Screening in Parkinson's disease patients from under-represented populations will increase our understanding of the role of LRRK2 variants in disease risk worldwide.

Lrrk2 mutations in South America: A study of Chilean Parkinson's disease

Pathogenic substitutions in the leucine-rich repeat kinase 2 protein (Lrrk2), R1441G and G2019S, are a prevalent cause of autosomal dominant and sporadic Parkinson's disease in the Northern Spanish population. In this study we examined the frequency of these two substitutions in 166 Parkinson's disease patients and 153 controls from Chile, a population with Spanish/European-Amerindian admixture. Lrrk2 R1441G was not observed, however Lrrk2 G2019S was detected in one familial and four sporadic Parkinson's disease patients. These findings suggest Lrrk2 G2019S may play an important role in Parkinson's disease on the South American Continent and further studies are now warranted.

Association of GST M1 null polymorphism with Parkinson's disease in a Chilean population with a strong Amerindian genetic component

We have studied the association of a null mutation of Glutathione Transferase M1 (GST M1*0/0) with Parkinson's disease (MIM 168600) in a Chilean population with a strong Amerindian genetic component. We determined the genotype in 349 patients with idiopathic Parkinson's disease (174 female and 175 male; 66.84+/-10.7 years of age), and compared that to 611 controls (457 female and 254 male; 62+/-13.4 years of age). A significant association of the null mutation in GST M1 with Parkinson's disease was found (p=0.021), and the association was strongest in the earlier age range. An association of GSTM1*0/0 with Parkinson's disease supports the hypothesis that Glutathione Transferase M1 plays a role in protecting astrocytes against toxic dopamine oxidative metabolism, and most likely by preventing toxic one-electron reduction of aminochrome.

[Sydenham's chorea. A clinical analysis of 55 patients with a prolonged follow-up]

INTRODUCTION

Sydenham's chorea is permanently on the rise in developing countries and may suddenly reappear in developed nations.

PATIENTS AND METHODS

We studied a prospective series of 55 cases, involving a total of 89 outbreaks with long-term follow-ups. All the cases were considered to be rheumatic from the outset, whether they were pure choreas or accompanied by the other signs from the Jones criterion, 38 and 17 respectively, in the first outbreak. Ages ranged between 7 and 22 years, with a mean of 15, at the time of the first outbreak; there was a predominance of females (87%).

RESULTS

Hemichorea accounted for 54% of cases. Presentation under treatment was mild (60%), moderate (27%) and severe (13%). Duration ranged from 30 to 365 days. Most of the patients presented just one outbreak and only 18% had multiple outbreaks, between 2 and 10 in number. Ballism was observed in five patients, a state of chorea in two of them, another two had chorea mollis and corea gravidarum was found in five of the patients. Chorea was associated to hypotonia, incoordination, fatigue, postural disorders, motor impersistence, dysarthria and altered gait. Psychiatric disorders were frequent and varied, the most predominant being anguish, irritability, psychomotor restlessness, obsessive-compulsive traits and insomnia. The only important sequela involved the heart, with 10 cases, two of which required surgery.

CONCLUSIONS

Crystalline penicillin was used to eradicate streptococcus, neuroleptic agents were employed to reduce involuntary movements and psychiatric symptoms, and benzathine was utilised as a prophylaxis for relapses and sequelae.