The first case report of McLeod syndrome in a Chinese patient

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.

The first case report of McLeod syndrome in an infant with a novel mutation (c.89C>A, p. 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.

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.

The first report of a Chinese family with McLeod syndrome

We report the first case of a Chinese family with McLeod syndrome (MLS). The two affected brothers show significant phenotypic heterogeneity. The index case has peripheral acanthocytosis, choreoathetosis of his feet, a slowly progressive neuropathy and myopathy, and an elevated serum creatine kinase (CK) level. His elder brother has more prominent chorea of the shoulders, epilepsy, a rapidly progressive neuropathy and normal serum CK. The diagnosis of MLS was confirmed by a genetic test which showed a hemizygous frameshift mutation in the XK gene.

Novel single base-pair deletion in exon 1 of XK gene leading to McLeod syndrome with chorea, muscle wasting, peripheral neuropathy, acanthocytosis and haemolysis

We present a 70-year-old male patient of Greek origin with choreatic movements of the tongue and face, lower limb muscle weakness, peripheral neuropathy, elevated creatinephosphokinase (CPK), acanthocytosis and haemolysis in the absence of Kell RBC antigens with an additional Factor IX-deficiency. Genetic testing for mutations in the three exons of the XK gene revealed a previously unreported hemizygous single base-pair frameshift deletion at exon 1 (c.229delC, p.Leu80fs). In conclusion, we hereby describe a rare phenotype of a patient with McLeod syndrome which was discovered coincidentally during routine blood group testing and consecutively genetically confirmed.