Clinical and genetic analysis of 29 Brazilian patients with Huntington's disease-like phenotype

Abstract

Huntington's disease (HD) is a neurodegenerative disorder characterized by chorea, behavioral disturbances and dementia, caused by a pathological expansion of the CAG trinucleotide in the HTT gene. Several patients have been recognized with the typical HD phenotype without the expected mutation. The objective of this study was to assess the occurrence of diseases such as Huntington's disease-like 2 (HDL2), spinocerebellar ataxia (SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and choreaacanthocytosis (ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not reached in 79.3% of the patients. HDL2 was the main cause of the HD-like phenotype in the group analyzed, and is attributable to the African ancestry of this population. However, the etiology of the disease remains undetermined in the majority of the HD negative patients with HD-like phenotype.

Huntington disease and Huntington disease‐like in a case series from Brazil

“…It is not a surprise that HDL2 was the second most common diagnosis. Our results confirm a previous report by Rodrigues et al (15), who evaluated the HD-like diseases among 66 patients recruited in the Southeast of Brazil, and found 37 with HD (56%), 3 HDL2 (4.5%), and 2 CHAC patients. In this series, HDL2 seemed to be more common in the Southeast than in other regions.…”

“…A review of the literature might suggest a gradient of frequency, where HTT expansions are much more prevalent among North‐Europeans, than in other populations. HD was diagnosed in 93% of 618 French and Moroccan , 82.8% of 169 Portuguese , 57% of 66 Brazilian and 50% of 11 South African black patients with a HD‐like phenotype. Brazilians have very mixed ancestries, and different regions of the country have a quite diverse population background.…”

Huntington's Disease, Huntington's Disease Look‐Alikes‎, and Benign Hereditary Chorea: What's New?

“…Only about 1% of suspected HD cases emerge as phenocopy syndromes . Approximately a dozen studies have systematically screened such cohorts of patients, with a clinical diagnosis consistent with HD but without the HD expansion for panels of genes causing HD phenocopies; however, a definite genetic diagnosis could only be reached in a small minority of them (2.1% of a total of 1,559 HDL patients screened) (see Fig. and Table ).…”

Huntington's disease like phenotype: new data from Brazil and what we know between heaven and earth

“…They found 3 patients with HDL2 and 2 patients with ChAc. The etiology of HDL was not found in 79,3% of the patients 19 . These findings suggest that HDL disorders are clinically and genetically very heterogeneous, and additional studies are needed to solve this intriguing problem 3,[10][11][12] .…”

“…Nevertheless, additional genetic studies confirm that the origin of the HDL2 mutation in that patient has most probably originated from an African ancestor [16][17][18] . In this issue of Arquivos de Neuro-Psiquiatra Rodrigues et al from Ribeirão Preto School of Medicine, University of São Paulo, in a collaborative study with the Neurology Department of School of Medical Sciences, University of Campinas, São Paulo, Mount Sinai School of Medicine, New York, USA, Ludwig-Maximilians-Universität, Munchen, Germany, and Hopital Pitié-Salpé-trière, Paris, France, present a very interesting study analyzing clinically and genetically 29 Brazilian patients with HDL phenotype 19 . In this group of HDL patients the authors studied the occurrence of HDL2, SCAs types 1, 2, 3, and 17, DRPLA, and chorea-acanthocytosis (ChAc).…”