Multisystem pathology in McLeod syndrome

We present a comprehensive characterization of clinical, neuropathological, and multisystem features of a man with genetically confirmed McLeod neuroacanthocytosis syndrome, including video and autopsy findings. A 61-year-old man presented with a movement disorder and behavioral change. Examination showed dystonic choreiform movements in all four limbs, reduced deep-tendon reflexes, and wide-based gait. He had oromandibular dyskinesia causing severe dysphagia. Elevated serum creatinine kinase (CK) was first noted in his thirties, but investigations, including muscle biopsy at that time, were inconclusive. Brain magnetic resonance imaging showed white matter volume loss, atrophic basal ganglia, and chronic small vessel ischemia. Despite raised CK, electromyography did not show myopathic changes. Exome gene panel testing was negative, but targeted genetic analysis revealed a hemizygous pathogenic variant in the XK gene c.895C > T p.(Gln299Ter), consistent with a diagnosis of McLeod syndrome. The patient died of sepsis, and autopsy showed astrocytic gliosis and atrophy of the basal ganglia, diffuse iron deposition in the putamen, and mild Alzheimer's pathology. Muscle pathology was indicative of mild chronic neurogenic atrophy without overt myopathic features. He had non-specific cardiomyopathy and splenomegaly. McLeod syndrome is an ultra-rare neurodegenerative disorder caused by X-linked recessive mutations in the XK gene. Diagnosis has management implications since patients are at risk of severe transfusion reactions and cardiac complications. When a clinical diagnosis is suspected, candidate genes should be interrogated rather than solely relying on exome panels.

Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as a possible feature

STUDY OBJECTIVES

McLeod syndrome is a very rare multisystemic neurodegenerative disease linked to mutations in the XK gene. It has cardiac, neurologic, and neuromuscular manifestations and shares similarities with Huntington's disease. The aim of this study was to evaluate sleep patterns of patients affected by McLeod syndrome.

METHODS

This retrospective case series of four males who underwent diagnostic polysomnography (mean age 53.8 ± 2.5 years) includes self-reported and objective evaluation of sleep using the Epworth Sleepiness Scale, genetic tests, documentation of clinical course and features, and laboratory-based full-night attended video-polysomnography.

RESULTS

In three out of four patients, an Epworth Sleepiness Scale score ≥ 7 was evident. The average apnea-hypopnea index was 45.0 ± 19.0, with predominantly obstructive phenotype in three patients and predominant central events (central sleep apnea syndrome) in one patient. A significantly increased periodic limb movement index during sleep was observed in all patients. All patients tolerated continuous positive airway pressure or pressure controlled therapy.

CONCLUSIONS

Polysomnography of all patients confirmed sleep apnea syndrome as a feature of McLeod syndrome. Three patients were diagnosed with obstructive sleep apnea and one with central sleep apnea syndrome. In addition, periodic limb movement index was increased in all patients.

CITATION

Dieter M, Kevin P, Tobias V, et al. Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as a possible feature. J Clin Sleep Med. 2024;20(3):339-344.

Proceedings of the Eleventh International Meeting on Neuroacanthocytosis Syndromes

The 11th International Meeting on Neuroacanthocytosis Syndromes was held on September 15th-17th, 2023 at the University Hospital Campus in Homburg/Saar, Germany. The meeting followed the previous ten international symposia, the last of which was held online due to restrictions due to COVID19, in March 2021. The setting of the meeting encouraged interactions, exchange of ideas, and networking opportunities among the participants from around the globe, including basic and clinical scientists, clinicians, and especially patients, their relatives and caregivers. A total of about 20 oral communications were presented in five scientific sessions accompanied by a keynote lecture, a "Poster-Blitz" session, the "Glenn Irvine Prize" lecture and a panel discussion about "Patient registries, international cooperation & future perspectives". In summary, attendees discussed recent advances and set the basis for the next steps, action points, and future studies in close collaboration with the patient associations, which were actively involved in the whole process.

A case of McLeod syndrome caused by a nonsense variation c.942G>A in the XK gene: A case report

McLeod syndrome is a rare XK gene-related progressive, debilitating disease involving multiple systems. The blood group phenotypes in McLeod syndrome patients usually display the Kx antigen loss and a decrease in the Kell blood group system antigen expression. This paper describes a 41-year-old male Chinese patient with McLeod syndrome. He first attended a hospital in 2015 and developed progressively worsening symptoms 4 years ago. As the disease progressed, the patient exhibited memory loss, unresponsiveness, and chorea and displayed elevated creatine kinase levels. However, McLeod syndrome could not be diagnosed by these signs and laboratory results. The patient was readmitted to the hospital in 2020 and was suspected of having McLeod syndrome. Serological analysis of the Kell blood group system and genotyping for the XK blood group system were performed, revealing the weak expression of the K antigen and the negative K antigen. Sequencing of the coding region of the XK gene showed a hemizygous c.942G>A variation in the XK gene, which resulted in a premature stop codon at position 314 (p.Trp314Ter). Therefore, the patient was diagnosed with McLeod syndrome. In conclusion, this paper presents a case of McLeod syndrome caused by a nonsense variation c.942G>A in the XK gene. The analysis of the XK gene and blood group antigen is helpful for the diagnosis of McLeod syndrome and for distinguishing it from many other diseases.

VPS13 Forum Proceedings: XK, XK-Related and VPS13 Proteins in Membrane Lipid Dynamics

In 2020, the pandemic interrupted the series of biannual International Neuroacanthocytosis Meetings that brought together clinicians, scientists, and patient groups to share research into a small group of devastating genetic diseases that combine both acanthocytosis (deformed red blood cells) and neurodegeneration with movement disorders. This Meeting Report describes talks at the 5th VPS13 Forum in January 2022, one of a series of online meetings held to fill the gap. The meeting addressed the basic biology of two key proteins implicated in chorea-acanthocytosis (mutations in VPS13A) and McLeod syndrome (mutations in XK). In a remarkable confluence of ideas, the speakers described different aspects of a single functional unit that comprises of VPS13A and XK proteins working together. Conditions caused by VPS13 (A-D) gene family mutations and related genes, such as XK, previously footnote knowledge, seem to turn central for a novel disease paradigm: bulk lipid transfer disorders.

Cardiac manifestation is evident in chorea-acanthocytosis but different from McLeod syndrome

INTRODUCTION

We aimed to study the various cardiac manifestations of the two core neuroacanthocytosis (NA) syndromes, namely chorea-acanthocytosis (ChAc) and McLeod syndrome (MLS). So far, cardiac involvement has been described as specific feature only for MLS.

METHODS

We studied six patients with ChAc (mean age 44.5 years, five men, one woman) and six patients with MLS (mean age 57.1 years, all men). Cardiac evaluation included echocardiography and/or cardiac magnetic resonance imaging (cardiac MRI), 24-h ECG-recording and examination of cardiac biomarkers.

RESULTS

Cardiac involvement of ChAc was found in four of six patients. Two patients showed mildly reduced left ventricular ejection fraction (LVEF), two other patients mild to moderate left ventricular (LV) dilatation. Neither an increase in ventricular ectopic beats nor ventricular tachycardia were evident in ChAc. Four of five MLS patients showed left ventricle dilatation and reduced left ventricular ejection fraction (LVEF). Two of these, in addition, had critical ventricular tachycardia. High sensitive troponin T was elevated in all patients, for whom data were available (n = 10). In contrast, elevation of high sensitive troponin I was found in one of six ChAc and one of two MLS patients.

CONCLUSION

For the first time, we reveal cardiac involvement in a cohort of six ChAc patients, while the risk to develop heart failure seems lower than in MLS. Our study confirms the malignant nature of MLS in terms of ventricular arrhythmias and progression to advanced heart failure. Herein, we define disease-specific recommendations for cardiac assessment in both conditions.

Proceedings of the Tenth International Meeting on Neuroacanthocytosis Syndromes

The 10th International Meeting on Neuroacanthocytosis Syndromes was held online on March 10th12th, 2021. The COVID19 pandemic situation made our planned meeting in Barcelona on March 2020 to be suspended by one year, and finally took place online. The meeting followed the previous nine international symposia, the last of which was held in Dresden, Germany in March, 2018. The setting of the meeting encouraged interactions, exchange of ideas and networking opportunities among the high number of participants from around the globe, including scientists, neurologists and specially patients and caregivers. A total of 27 oral communications were distributed in 8 sessions with topics ranging from molecular and cellular functions of VPS13 genes and proteins, their involvement in Neuroacanthocytosis Syndromes and finally clinical aspects and patients care. In addition, 5 posters were presented. Altogether, scientists and neurologists discussed recent advances and set the bases for next steps, action points, and future studies in close collaboration with the patients associations, which are always actively involved in the whole process.

Neuroacanthocytosis Syndromes in an Italian Cohort: Clinical Spectrum, High Genetic Variability and Muscle Involvement

Neuroacanthocytosis (NA) syndromes are a group of genetically defined diseases characterized by the association of red blood cell acanthocytosis, progressive degeneration of the basal ganglia and neuromuscular features with characteristic persistent hyperCKemia. The main NA syndromes include autosomal recessive chorea-acanthocytosis (ChAc) and X-linked McLeod syndrome (MLS). A series of Italian patients selected through a multicenter study for these specific neurological phenotypes underwent DNA sequencing of the VPS13A and XK genes to search for causative mutations. Where it has been possible, muscle biopsies were obtained and thoroughly investigated with histochemical assays. A total of nine patients from five different families were diagnosed with ChAC and had mostly biallelic changes in the VPS13A gene (three nonsense, two frameshift, three splicing), while three patients from a single X-linked family were diagnosed with McLeod syndrome and had a deletion in the XK gene. Despite a very low incidence (only one thousand cases of ChAc and a few hundred MLS cases reported worldwide), none of the 8 VPS13A variants identified in our patients is shared by two families, suggesting the high genetic variability of ChAc in the Italian population. In our series, in line with epidemiological data, McLeod syndrome occurs less frequently than ChAc, although it can be easily suspected because of its X-linked mode of inheritance. Finally, histochemical studies strongly suggest that muscle pathology is not simply secondary to the axonal neuropathy, frequently seen in these patients, but primary myopathic alterations can be detected in both NA syndromes.

"Neuroacanthocytosis" - Overdue for a Taxonomic Update

The term "neuroacanthocytosis" (NA) is used for a spectrum of neurological disorders in which there are thorny red blood cells. While NA historically referred to disorders of lipoprotein absorption, we have promoted it as an overarching term for a group of basal ganglia disorders, with specific reference to two diseases that we defined as "core" NA syndromes. "Neuroacanthocytosis" has also been used to refer to a specific, now genetically-defined disease, otherwise known as "chorea-acanthocytosis". These various usages have resulted in diagnostic confusion, and in a number of cases have quite likely prevented the pursuance of precise, molecular, diagnosis. Disease nomenclature is an ever-evolving field, especially in the current era of expanding genetics, and naming proposals are often far from ideal. We, however, suggest that the term "neuroacanthocytosis" should no longer be generally used and if so, only with appropriate understanding of its limitations. Further, we propose that chorea-acanthocytosis be renamed as "VPS13A disease" in accordance with its genetic etiology.

A patient with McLeod syndrome showing involvement of the central sensorimotor tracts for the legs

Background

McLeod syndrome is a rare X-linked recessive acanthocytosis associated with neurological manifestations including progressive chorea, cognitive impairment, psychiatric disturbances, seizures, and sensorimotor axonal polyneuropathy. However, no studies have investigated the functioning of central sensorimotor tracts in patients with McLeod syndrome.

Case presentation

A 66-year-old man had experienced slowly progressive chorea and gait disturbance due to lower limb muscle weakness since his early fifties. Blood examinations showed erythrocyte acanthocytosis and the reduction of Kell antigens in red blood cells. Brain magnetic resonance imaging showed atrophy of the bilateral caudate nuclei and putamen. The diagnosis of McLeod syndrome was confirmed by the presence of a mutation of the XK gene on the X chromosome. Somatosensory-evoked potential and transcranial magnetic stimulation studies demonstrated that the central sensory and motor conduction times were abnormally prolonged for the lower extremity but normal for the upper extremity.

Conclusions

This is the first report of the involvement of the central sensorimotor tracts for the legs in a patient with McLeod syndrome. The clinical neurophysiological technique revealed the central sensorimotor tracts involvements clinically masked by neuropathy.

Ser30X) in XK

McLeod syndrome (MLS) is a rare multisystem disorder and X-linked recessive inheritance disorder caused by mutations of the X-linked Kx blood group (XK) gene. The manifestations progress slowly and mainly appear in middle age, which make it difficult to distinguish MLS from other neuromuscular disorders. Here, we present a case of a 10-month-old Chinese boy who was taken to hospital for herpes of the extremities and oral cavity along with febrile seizures in June 2017. The laboratory test revealed persistent elevated levels of serum creatine phosphokinase and abnormal liver function. The results of the electrocardiogram showed sinus tachycardia, and magnetic resonance imaging of the brain showed enlarged bilateral ventricles and third ventricle. Genetic analysis by next-generation sequencing revealed a novel nonsense mutation c.89C > A (p. Ser30X) in exon 1 of XK. To the best of our knowledge, this is the first case report of infants with MLS confirmed by genetic analysis.

McLeod syndrome: Five new pedigrees with novel mutations

OBJECTIVE

To present five new McLeod Syndrome (MLS) pedigrees with novel XK gene mutations, review the literature of this disorder, and discuss the typical and atypical clinical features noted with these new mutations.

METHODS

This is a multi-center retrospective review of five MLS cases with novel gene mutations. Genotypic and phenotypic information has been obtained from each center.

RESULTS

Five novel mutations are reported in this Case series. New clinical findings include prolonged asymptomatic elevated creatine kinase (CK) levels, vocal tics, presence of obstructive sleep apnea (OSA), and one patient of Vietnamese ethnicity.

CONCLUSIONS

We expand on the clinical and genetic spectrum of MLS demonstrating the clinical variability of MLS.

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.

Neuroacanthocytosis in china: a review of published reports

Background

Neuroacanthocytosis (NA) syndromes are a group of rare diseases characterized by the presence of acanthocytes and neuronal multisystem pathology, including chorea-acanthocytosis (ChAc), McLeod syndrome (MLS), Huntington's disease-like 2 (HDL-2), and pantothenate kinase-associated neurodegeneration (PKAN). China has the largest population in the world, which makes it a good location for investigating rare diseases like NA.

Methods

We searched Medline, ISI Proceedings, China National Knowledge Infrastructure, and Wanfang Data for literature published through December 31, 2013 for all the published Chinese NA case reports and extracted the clinical and laboratory findings.

Results

A total of 42 studies describing 66 cases were found to be eligible for inclusion. Age of symptom onset ranged from 5 to 74 years. The most common findings included hyperkinetic movements (88%), orofacial dyskinesia (80%), dystonia (67%), and dysarthria (68%), as well as caudate atrophy or enlarged lateral ventricles on neuroimaging (64%), and elevated creatine kinase (52%). Most cases were not confirmed by any specific molecular tests. Only two cases were genetically studied and diagnosed as ChAc or MLS.

Discussion

In view of the prevalence of NA syndromes in other countries, the number of patients in China appears to be underestimated. Chinese NA patients may benefit from the establishment of networks that offer specific diagnoses and care for rare diseases.

Henry VIII, McLeod syndrome and Jacquetta's curse

The mental decline of King Henry VIII from being a jovial, charismatic and athletic young man into an increasingly paranoid, brutal tyrant in later life, ever more concerned at his lack of one or more male heirs, has attracted many medical diagnostic theories. Previous hypotheses have included diabetes, syphilis and hypothyroidism, among others. However, these inadequately explain Henry's failure to produce a male heir, despite multiple pairings. The latest postulated diagnoses for Henry are the coexistence of both Kell blood group antigenicity (possibly inherited from Jacquetta Woodville, Henry's maternal great grandmother) causing related impaired fertility, and McLeod syndrome, causing psychotic changes. As the mutated McLeod protein of the syndrome significantly reduces the expression, effectively inactivating the Kell antigen, we critically review this theory, examining in detail the pathophysiology of these conditions and assessing the genealogy of Henry VIII and its effect in subsequent generations.

Clinical and molecular research of neuroacanthocytosis

Neuroacanthocytosis is an autosomal recessive or dominant inherited disease characterized by widespread, non-specific nervous system symptoms, or spiculated "acanthocytic" red blood cells. The clinical manifestations typically involve chorea and dystonia, or a range of other movement disorders. Psychiatric and cognitive symptoms may also be present. The two core neuroacanthocytosis syndromes, in which acanthocytosis is atypical, are autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome. Acanthocytes are found in a smaller proportion of patients with Huntington's disease-like 2 and pantothenate kinase-associated neurodegeneration. Because the clinical manifestations are diverse and complicated, in this review we present features of inheritance, age of onset, neuroimaging and laboratory findings, as well as the spectrum of central and peripheral neurological abnormalities and extraneuronal involvement to help distinguish the four specific syndromes.

Mcleod syndrome: Report of an Indian family with phenotypic heterogeneity

The present report deals with the clinical phenomenology of three members (brothers) of one family with McLeod syndrome (MLS). In two, the clinical pictures were of choreiform disorders with amyotrophy, which were found to be neurogenic in origin by detailed electrophysiological study. The index case had peripheral acanthocytosis; immunohematological and molecular genetic studies confirmed diagnosis of MLS. However, one brother only had a slowly progressive motor neuron disease like picture but no abnormal movement disorder. He had peripheral acanthocytes as well. The inheritance seems to be X-linked recessive in nature. The affected family members exhibited much phenotypic heterogeneity. This appears to be the first report of MLS from India.