Head drops are also observed in McLeod syndrome

Brain F-18 FDG and F-18 FP-CIT PET/CT Findings of c.856_860delCTCTA Mutation McLeod Syndrome

McLeod syndrome is a rare X-linked recessive genetic disorder that is caused by mutations of the XK gene. It is one of the core neuroacanthocytosis syndromes. We report the case of a 67-year-old man who presented to Kyungpook National University Hospital in the Republic of Korea with progressive worsening of generalized chorea and dystonia. He had no recognized family history of neurologic illness. A peripheral blood smear showed increased acanthocytes. His serum creatine kinase levels were 894 U/L. A brain MRI showed atrophy of the bilateral striatal nuclei. An F-18 F-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane PET/CT showed moderately decreased dopamine transporter uptake in the putamen and severely decreased uptake in the caudate nucleus. An F-18 fludeoxyglucose PET/CT demonstrated markedly decreased metabolism at the caudate nucleus and the putamen. Whole exome sequencing revealed hemizygous pathogenic mutations of the XK gene (c.856_860delCTCTA;p.Leu286TyrfsTer16). We believe that these findings provide useful information regarding the clinical features of individuals with McLeod syndrome.

Chorea

PURPOSE OF REVIEW

This article reviews the clinical approach to the diagnosis of adult patients presenting with chorea, using Huntington disease (HD) as a point of reference, and presents the clinical elements that help in the diagnostic workup. Principles of management for chorea and some of the associated features of other choreic syndromes are also described.

RECENT FINDINGS

Mutations in the C9orf72 gene, previously identified in families with a history of frontotemporal dementia, amyotrophic lateral sclerosis, or both, have been recognized as one of the most prevalent causes of HD phenocopies in the white population.

SUMMARY

The diagnosis of chorea in adult patients is challenging. A varied number of associated causes require a physician to prioritize the investigations, and a detailed history of chorea and associated findings will help. For chorea presenting as part of a neurodegenerative syndrome, the consideration of a mutation in the C9orf72 gene is a new recommendation after excluding HD. There are no new treatment options for chorea, aside from dopamine blockers and tetrabenazine. There are no disease-modifying treatments for HD or other neurodegenerative choreic syndromes.

Management of Neuroacanthocytosis Syndromes

BACKGROUND

The two core neuroacanthocytosis (NA) syndromes, chorea-acanthocytosis (ChAc) and McLeod syndrome, are progressive neurodegenerative disorders that primarily affect the basal ganglia. The characteristic phenotype comprises a variety of movement disorders including chorea, dystonia, and parkinsonism, as well as psychiatric and cognitive symptoms attributable to basal ganglia dysfunction. These disorders are symptomatically managed on a case-by-case basis, with very few practitioners seeing more than a single case in their careers.

METHODS

A literature search was performed on PubMed utilizing the terms neuroacanthocytosis, chorea-acanthocytosis, and McLeod syndrome, and articles were reviewed for mentions of therapies, successful or otherwise.

RESULTS

There have been no blinded, controlled trials and only one retrospective case series describing ChAc. The various therapies that have been used in patients with NA syndromes are summarized.

DISCUSSION

Management remains at present purely symptomatic, which is similar in principle to other more common basal ganglia neurodegenerative disorders such as Huntington's disease (HD) and Parkinson's disease (PD). However, there are some specific issues particular to NA syndromes that merit attention. An integrated multidisciplinary approach is the ideal management strategy for these complex and multifaceted neurodegenerative disorders.

Untangling the Thorns: Advances in the Neuroacanthocytosis Syndromes

There have been significant advances in neuroacanthocytosis (NA) syndromes in the past 20 years, however, confusion still exists regarding the precise nature of these disorders and the correct nomenclature. This article seeks to clarify these issues and to summarise the recent literature in the field. The four key NA syndromes are described here-chorea-acanthocytosis, McLeod syndrome, Huntington's disease-like 2, and pantothenate kinase- associated neurodegeneration. In the first two, acanthocytosis is a frequent, although not invariable, finding; in the second two, it occurs in approximately 10% of patients. Degeneration affecting the basal ganglia is the key neuropathologic finding, thus the clinical presentations can be remarkably similar. The characteristic phenotype comprises a variety of movement disorders, including chorea, dystonia, and parkinsonism, and also psychiatric and cognitive symptoms attributable to basal ganglia dysfunction. The age of onset, inheritance patterns, and ethnic background differ in each condition, providing diagnostic clues. Other investigations, including routine blood testing and neuroimaging can be informative. Genetic diagnosis, if available, provides a definitive diagnosis, and is important for genetic counseling, and hopefully molecular therapies in the future. In this article I provide a historical perspective on each NA syndrome. The first 3 disorders, chorea-acanthocytosis, McLeod syndrome, Huntington's disease-like 2, are discussed in detail, with a comprehensive review of the literature to date for each, while pantothenate kinase-associated neurodegeneration is presented in summary, as this disorder has recently been reviewed in this journal. Therapy for all of these diseases is, at present, purely symptomatic.

Brain, blood, and iron: perspectives on the roles of erythrocytes and iron in neurodegeneration

The terms "neuroacanthocytosis" (NA) and "neurodegeneration with brain iron accumulation" (NBIA) both refer to groups of genetically heterogeneous disorders, classified together due to similarities of their phenotypic or pathological findings. Even collectively, the disorders that comprise these sets are exceedingly rare and challenging to study. The NBIA disorders are defined by their appearance on brain magnetic resonance imaging, with iron deposition in the basal ganglia. Clinical features vary, but most include a movement disorder. New causative genes are being rapidly identified; however, the mechanisms by which mutations cause iron accumulation and neurodegeneration are not well understood. NA syndromes are also characterized by a progressive movement disorder, accompanied by cognitive and psychiatric features, resulting from mutations in a number of genes whose roles are also basically unknown. An overlapping feature of the two groups, NBIA and NA, is the occurrence of acanthocytes, spiky red cells with a poorly-understood membrane dysfunction. In this review we summarise recent developments in this field, specifically insights into cellular mechanisms and from animal models. Cell membrane research may shed light upon the significance of the erythrocyte abnormality, and upon possible connections between the two sets of disorders. Shared pathophysiologic mechanisms may lead to progress in the understanding of other types of neurodegeneration.