Two McLeod patients with novel mutations in XK

Systematic review of phenotypes in McLeod syndrome and case report of a progressive supranuclear palsy in a female carrier

INTRODUCTION

We present a systematic review of phenotypes of McLeod syndrome (MLS) and a case of a 73-year-old female carrier of the genetic alteration leading to MLS with the typical progressive supranuclear palsy (PSP) phenotype.

METHODS

To facilitate clinical reasoning and enable targeted diagnosis, we conducted a systematic review of the papers describing symptomatic cases of confirmed McLeod syndrome. This review follows the PRISMA 2020 statement: an updated guideline for reporting systematic reviews (Page et al in Syst Rev 10(1):89, 2021).

RESULTS

The average onset of MLS was at 40.2 years of age with chorea (46%), seizures and psychiatric changes (each 13%). Very common are weakened Kell antigen (100%), changes in muscle biopsy (100%), genetic alterations in XK (100%), elevated creatine kinase (97%), acanthocytes (96%), MRI changes (95%), chorea (84%) and hyporeflexia (82%).

CONCLUSION

This review of 65 males and 11 females gives a concise overview of clinical phenotypes in MLS, reinforcing our view that this female patient had PSP independent of MLS carrier status. This report highlights the pitfalls of anchoring in medical decision-making, particularly the possible diagnostic bias of a known genetic carrier status of a very rare disease.

Does aberrant membrane transport contribute to poor outcome in adult acute myeloid leukemia?

Acute myeloid leukemia in adults is a highly heterogeneous disease. Gene expression profiling performed using unsupervised algorithms can be used to distinguish specific groups of patients within a large patient cohort. The identified gene expression signatures can offer insights into underlying physiological mechanisms of disease pathogenesis. Here, the analysis of several related gene expression clusters associated with poor outcome, worst overall survival and highest rates of resistant disease and obtained from the patients at the time of diagnosis or from previously untreated individuals is presented. Surprisingly, these gene clusters appear to be enriched for genes corresponding to proteins involved in transport across membranes (transporters, carriers and channels). Several ideas describing the possible relationship of membrane transport activity and leukemic cell biology, including the "Warburg effect," the specific role of chloride ion transport, direct "import" of metabolic energy through uptake of creatine phosphate, and modification of the bone marrow niche microenvironment are discussed.

Molecular Basis of KELnull Phenotype in Brazilians

BACKGROUND

KELnull (K0) persons can produce clinically significant anti-KEL5 antibody after transfusion and/or pregnancy, requiring K0 blood transfusion when indicated. 37 K0 alleles have been reported in studies over different populations, but none in Amerindian-Caucasian descendants from South America. The aim of this study was to identify the molecular basis of K0 phenotype in Brazilians.

METHODS

We investigated three K0 samples from different Brazilian blood banks (Recife, Manaus, and Vila Velha) in women with anti-KEL5. KEL antigen typing was performed by serologic techniques, and the K0 status was confirmed by flow cytometry. PCR-RFLP and DNA sequencing of the KEL coding and exon-intron regions were also performed.

RESULTS

RBCs of the 3 patients were phenotyped as KEL:-1,-2,-3,-4,-7. The 3 patients had the same KEL*02/02 genotype and were negative for KEL*02.03 and KEL*02.06 alleles. The Recife K0 patient was homozygous for IVS16 + 1g>a mutation (KEL*02N.31 allele). The flow cytometry with anti-KEL1, anti-KEL2, anti-KEL3, anti-KEL4, and anti-CD238 confirmed the K0 phenotype. In addition, we found the c.10423C>T mutation (KEL*02N.04 allele) in both the Manaus K0 and the Vila Velha K0 patients.

CONCLUSION

This report represents the first study of K0 molecular basis performed in Amerindian-Caucasian descendants from South America.