Erratum: Variable frequency of LRRK2 variants in the Latin American research consortium on the genetics of Parkinson's disease (LARGE-PD), a case of ancestry.

[This corrects the article DOI: 10.1038/s41531-017-0020-6.].

Variable frequency of LRRK2 variants in the Latin American research consortium on the genetics of Parkinson's disease (LARGE-PD), a case of ancestry.

Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2), primarily located in codons G2019 and R1441, represent the most common genetic cause of Parkinson's disease in European-derived populations. However, little is known about the frequency of these mutations in Latin American populations. In addition, a prior study suggested that a LRRK2 polymorphism (p.Q1111H) specific to Latino and Amerindian populations might be a risk factor for Parkinson's disease, but this finding requires replication. We screened 1734 Parkinson's disease patients and 1097 controls enrolled in the Latin American Research Consortium on the Genetics of Parkinson's disease (LARGE-PD), which includes sites in Argentina, Brazil, Colombia, Ecuador, Peru, and Uruguay. Genotypes were determined by TaqMan assay (p.G2019S and p.Q1111H) or by sequencing of exon 31 (p.R1441C/G/H/S). Admixture proportion was determined using a panel of 29 ancestry informative markers. We identified a total of 29 Parkinson's disease patients (1.7%) who carried p.G2019S and the frequency ranged from 0.2% in Peru to 4.2% in Uruguay. Only two Parkinson's disease patients carried p.R1441G and one patient carried p.R1441C. There was no significant difference in the frequency of p.Q1111H in patients (3.8%) compared to controls (3.1%; OR 1.02, p = 0.873). The frequency of LRRK2-p.G2019S varied greatly between different Latin American countries and was directly correlated with the amount of European ancestry observed. p.R1441G is rare in Latin America despite the large genetic contribution made by settlers from Spain, where the mutation is relatively common.

Homocistinuria, una enfermedad metabólica de diagnóstico tardío en el Perú / Homocystinuria, a metabolic disease of late diagnosis in Peru

La Homocistinuria, es un desorden metabólico autosómico recesivo, cuya forma clásica es causada por deficiencia de cistationina β-sintasa, debido a mutaciones en el gen CBS (Cr 21q22.3). Se describe el caso de un varón de 17 años con hipopigmentación de piel y faneras, retraso psicomotor moderado, hábito marfanoide, miopía severa, subluxación del cristalino bilateral, que además presentó eventos psicóticos y una hemiparesia izquierda secundaria a un infarto lacunar. La determinación de homocisteína en plasma se encontró elevada (>9,9mg/dl), así como niveles altos de nitroprusiato de sodio en orina (4+) que confirmaron el diagnóstico clínico de homocistinuria. La homocistinuria clásica genera múltiples complicaciones a nivel dérmico, oftalmológico, cognitivo, osteoarticular y psiquiátrico; que podrían evitarse con un diagnóstico y tratamiento oportuno a través del tamizaje neonatal, aún no disponible en la mayoría de centros asistenciales en el Perú...

Homocystinuria is an autosomal-recessive metabolic disorder whose classical phenotype is caused by a deficiency of cystathionine β-synthase, due to mutations within the CBS gene (Cr21q22.3). Herein we report a 17 year old man with hypopigmented skin and hair, mental retardation, marfanoid habitus, severe myopia, bilateral lens subluxation, psychotic episodes, and left-sided hemiparesis secondary to a lacunar brain infarction. Laboratory tests showed increased levels of homocysteine (>9.9mg/dl) in plasma and high levels of urinary sodium nitroprusside (4+), consistent with the clinical diagnosis of classical homocystinuria. This systemic disorder includes dermal, ophthalmic, cognitive, osteoarticular and psychiatric alterations, all of which could be potentially prevented with early diagnosis and therapy as part of newborn screening, which is still unavailable in Peru...

Clinical and Molecular Features of Late Onset Huntington Disease in a Peruvian Cohort.

BACKGROUND: Late onset cases of Huntington disease (HD), with onset ≥60 years, account for up to 20% of HD cases worldwide. Clinical features include mild motor dysfunction with slow progression and cognitive impairment, frequent absence of family history and low number of CAG repeats. The clinical and molecular features of late onset HD is still understudied in Latin America. OBJECTIVES: To describe the clinical and molecular characteristics of late onset HD in a Peruvian cohort. METHODS: An observational study was carried out by reviewing the HD registry at the Neurogenetics Research Center-INCN from 2000 to 2014. Genotyping of HTT gene …was confirmed using standard PCR and PAGE in accordance to protocols previously established. RESULTS: Thirty-one late onset HD cases from 27 pedigrees were identified (9.42% of total HD cases, n = 329), 51.61% were male. Mean age at onset was 64.1 ± 4.2 and CAG repeats mean was 42.5 ± 2.5. We did not find significant correlation between age at onset and CAG repeats. 33.3% of cases were traced back to Cañete valley. Twenty-two cases had a positive family history, 14 of them with paternal transmission. Choreic movements and cognitive impairment were the main existing manifestations reported in this cohort, with lower frequency of psychiatric disturbances. CONCLUSIONS: This report of late onset HD affected individuals shows a mild phenotype expression of the disease, associated with low range of CAG repeats and up to 30% of cases with absence of clear family history. Cañete valley remains the region with more cases.

Neurogenetics in Peru: clinical, scientific and ethical perspectives.

Neurogenetics, the science that studies the genetic basis of the development and function of the nervous system, is a discipline of recent development in Peru, an emerging Latin American country. Herein, we review the clinical, scientific and ethical aspects regarding the development of this discipline, starting with the first molecular diagnosis of neurogenetic diseases, to family and population-based genetic association studies. Neurogenetics in Peru aims to better explain the epidemiology of monogenic and complex neurodegenerative disorders that will help in implementing public health policies for these disorders. The characterization of Peru and its health system, legal issues regarding rare diseases and the historical milestones in neurogenetics are also discussed.