Huntington's Disease-like Syndromes Research Articles

Spinocerebellar ataxia 48 presenting with ataxia associated with cognitive, psychiatric, and extrapyramidal features: A report of two Italian families

IntroductionSpinocerebellar ataxia 48 has recently been described as an adult onset ataxia associated with a cerebellar cognitive affective syndrome, caused by a heterozygous mutation in the STUB1 gene. MethodsWe characterized the clinical and neuroimaging phenotype of eight patients from two autosomal dominant ataxia multigenerational Italian families, in whom we conducted whole exome sequencing, targeted multigene sequencing, and Sanger sequencing studies. ResultsWe describe a complex syndrome characterized by ataxia and cognitive-psychiatric disorder in all cases, variably associated with chorea, parkinsonism, dystonia, urinary symptoms, and epilepsy. MRI showed a significant cerebellar atrophy, coupled to a T2-weighted hyperintensity affecting the dentate nuclei and extending to the middle cerebellar peduncles, whereas FDG-PET studies revealed glucose hypometabolism in cerebellum, striatum, and cerebral cortex.We identified two different novel STUB1 mutations segregating in the two families. One of the two mutations, p.(Gly33Ser), occurs in the TRP domain, whereas p.(Pro228Ser) is located in the ubiquitin ligase region. DiscussionWe emphasize the similarity of the described clinical picture with that of SCAR16, an autosomal recessive ataxia caused by biallelic mutations in the same gene, and of spinocerebellar ataxia type 17, which is considered the main Huntington's disease-like syndrome. The pathogenesis of the disease and the relationship between SCA48 and SCAR16 remain to be clarified.

Xeroderma pigmentosum is a definite cause of Huntington's disease-like syndrome.

Xeroderma pigmentosum is characterized by cutaneous, ophthalmological, and neurological features. Although it is typical of childhood, late presentations can mimic different neurodegenerative conditions. We report two families presenting as Huntington's disease‐like syndromes. The first case (group G) presented with neuropsychiatric features, cognitive decline and chorea. Typical lentigines were only noticed after the neurological disease started. The second case (group B) presented adult‐onset chorea and neuropsychiatric symptoms after an aggressive ocular melanoma. Xeroderma pigmentosum can manifest as a Huntington's Disease‐like syndrome. Classic dermatological and oncological features have to be investigated in choreic patients with negative genetic tests for Huntington's disease‐like phenotypes.

C9ORF72 repeat expansion is not a significant cause of late onset cerebellar ataxia syndrome

The GGGGCC hexanucleotide expansion in the C9ORF72 gene is the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in Caucasian populations. The phenotypic spectrum of C9ORF72 hexanucleotide repeat expansion mutation has been reported to include parkinsonian syndrome, Huntington's disease-like syndrome and dementia syndrome. Although few individuals with cerebellar ataxia have also anecdotally been found to harbor the mutation, the relationship between the mutation and cerebellar ataxia awaits further clarification. We hereby screened for the presence of the C9ORF72 hexanucleotide repeat expansion in 331 patients with multiple system atrophy-cerebellar variant and 98 unrelated patients with molecularly un-assigned spinocerebellar ataxia in Taiwan utilizing a repeat-primed polymerase chain reaction assay. We found that none of the 429 patients had the C9ORF72 hexanucleotide repeat expansion mutation. Therefore, our study does not support that the mutation plays a significant role in cerebellar ataxia.

C9ORF72 Mutations in Neurodegenerative Diseases

Recent works have demonstrated an expansion of the GGGGCC hexanucleotide repeat in the first intron of chromosome 9 open reading frame 72 (C9ORF72), encoding an unknown C9ORF72 protein, which was responsible for an unprecedented large proportion of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) cases of European ancestry. C9ORF72 is expressed in most tissues including the brain. Emerging evidence has demonstrated that C9ORF72 mutations could reduce the level of C9ORF72 variant 1, which may influence protein expression and the formation of nuclear RNA foci. The spectrum of mutations is broad and provides new insight into neurological diseases. Clinical manifestations of diseases related with C9ORF72 mutations can vary from FTD, ALS, primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), Huntington disease-like syndrome (HDL syndrome), to Alzheimer's disease. In this article, we will review the brief characterizations of the C9ORF72 gene, the expansion mutations, the related disorders, and their features, followed by a discussion of the deficiency knowledge of C9ORF72 mutations. Based on the possible pathological mechanisms of C9ORF72 mutations in ALS and FTD, we can find new targets for the treatment of C9ORF72 mutation-related diseases. Future studies into the mechanisms, taking into consideration the discovery of those disorders, will significantly accelerate new discoveries in this field, including targeting identification of new therapy.

Large C9orf72 Hexanucleotide Repeat Expansions Are Seen in Multiple Neurodegenerative Syndromes and Are More Frequent Than Expected in the UK Population

Hexanucleotide repeat expansions in C9orf72 are a major cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Understanding the disease mechanisms and a method for clinical diagnostic genotyping have been hindered because of the difficulty in estimating the expansion size. We found 96 repeat-primed PCR expansions: 85/2,974 in six neurodegenerative diseases cohorts (FTLD, ALS, Alzheimer disease, sporadic Creutzfeldt-Jakob disease, Huntington disease-like syndrome, and other nonspecific neurodegenerative disease syndromes) and 11/7,579 (0.15%) in UK 1958 birth cohort (58BC) controls. With the use of a modified Southern blot method, the estimated expansion range (smear maxima) in cases was 800-4,400. Similarly, large expansions were detected in the population controls. Differences in expansion size and morphology were detected between DNA samples from tissue and cell lines. Of those in whom repeat-primed PCR detected expansions, 68/69 were confirmed by blotting, which was specific for greater than 275 repeats. We found that morphology in the expansion smear varied among different individuals and among different brain regions in the same individual. Expansion size correlated with age at clinical onset but did not differ between diagnostic groups. Evidence of instability of repeat size in control families, as well as neighboring SNP and microsatellite analyses, support multiple expansion events on the same haplotype background. Our method of estimating the size of large expansions has potential clinical utility. C9orf72-related disease might mimic several neurodegenerative disorders and, with potentially 90,000 carriers in the United Kingdom, is more common than previously realized.

F25 Clinical criteria of Huntington's disease phenocopies and cases in Czech Republic

Huntington's disease (HD) is well-defined autosomal dominantly inherited disease with motor, cognitive and behavioural abnormalities. There is a small, but significant number of patients with symptoms typical for HD, but...

Huntington's disease phenocopy syndromes

Patients presenting with features of Huntington's disease but lacking the causative genetic expansion can be challenging diagnostically. The differential diagnosis of such Huntington's disease phenocopy syndromes has not recently been reviewed. Cohort studies have established the relative frequencies of known Huntington's disease phenocopy syndromes, whereas newly described ones have been characterized genetically, clinically, radiologically and pathologically. About 1% of suspected Huntington's disease cases emerge as phenocopy syndromes. Such syndromes are clinically important in their own right but may also shed light on the pathogenesis of Huntington's disease. Huntington's disease produces a range of clinical phenotypes, and the range of syndromes that may be responsible for Huntington's disease phenocopies is correspondingly wide. Cohort studies have established that, while the majority of phenocopy patients remain undiagnosed, in those patients where a genetic diagnosis is reached the commonest causes are SCA17, Huntington's disease-like syndrome 2 (HDL2), familial prion disease and Friedreich's ataxia. We review the features of the reported genetic causes of Huntington's disease phenocopy syndromes, including HDL1-3, SCA17, familial prion disease, spinocerebellar ataxias, dentatorubral-pallidoluysian atrophy, chorea-acanthocytosis and iron-accumulation disorders. We present an evidence-based framework for the genetic testing of Huntington's disease phenocopy cases.

The Huntington's disease-like syndromes: what to consider in patients with a negative Huntington's disease gene test

Huntington's disease (HD), which is caused by a triplet-repeat expansion in the IT15 gene (also known as huntingtin or HD), accounts for about 90% of cases of chorea of genetic etiology. In recent years, several other distinct genetic disorders have been identified that can present with a clinical picture indistinguishable from that of HD. These disorders are termed Huntington's disease-like (HDL) syndromes. So far, four such conditions have been recognized, namely disorders attributable to mutations in the prion protein gene (HDL1), the junctophilin 3 gene (HDL2), and the gene encoding the TATA box-binding protein (HDL4/SCA17), and a recessively inherited HD phenocopy in a single family (HDL3), the genetic basis of which is currently poorly understood. These disorders, however, account for only a small proportion of cases with the HD phenotype but a negative genetic test for HD, and the list of HDL genes and conditions is set to grow. In this article, we review the most important HD phenocopy disorders identified to date and discuss the clinical clues that guide further investigation. We will concentrate on the four so-called HDL syndromes mentioned above, as well as other genetic disorders such as dentatorubral-pallidoluysian atrophy, neuroferritinopathy, pantothenate-kinase-associated neurodegeneration and chorea-acanthocytosis.

Phenotypic homogeneity of the Huntington disease–like presentation in a SCA17 family

We describe clinical and genetic analysis of a family with spinocerebellar ataxia 17 (SCA17) presenting with a Huntington disease-like (HDL) syndrome. Clinically diagnosed, HD is genetically heterogeneous. Differential diagnosis includes SCA17. However, SCA17 HDL presentation has been observed only sporadically or in solitary individuals within a family. HDL phenotypic homogeneity in SCA17 has not been described. SCA17 can present with a HDL syndrome in multiple family members.