While McLeod syndrome is much rarer even than Chorea-acanthocytosis, it appears as if the methods of next generation sequencing allow more patients to be diagnosed. This is at least the impression of Adrian Danek at the Neurology Department at the University of Munich and of his colleagues at its neuromuscular unit (Friedrich Baur Institute). He had cared for a Munich patient and his brother almost thirty years ago but no other patients were diagnosed until 2018. In the last year, however, three new patients, men in their fifties who had presented with peripheral nerve and muscle issues, received a diagnosis of McLeod syndrome on the basis of genetic panel testing which was confirmed by immunohematological testing for the McLeod phenotype.
Interestingly, the modern genetic methods thus have fully reversed the previous, classical approach that starts with blood bank typing of the patient's red cells. Prof. Danek was invited to present a review of the syndrome at the Institute's comprehensive annual neuromuscular seminar that covers new findings from the whole field of muscle and peripheral nerve disease and in 2019 it took place on November 16.
McLeod Syndrome: He pointed out the new patient's initial presentation with loss of leg muscle bulk (atrophy) that mirrored the original index patient’s. A major practical problem for McLeod patients in Germany in general concerns is the issue of banking their blood donations for the future use of themselves or of others affected by the syndrome.
The three new Munich patients are being comprehensively studied in order to better understand the protean manifestations of McLeod syndrome that may affect brain control of movements, including swallowing, and that may be associated with epilepsy, personality changes and involvement of the heart muscle. The latter situation makes regular cardiology consults necessary and the uncommon McLeod phenotype of blood may cause transfusion hazards. Finally, boys that suffer from septic granulomatosis, a disease of antimicrobial defense that is caused by mutations in a gene right next to the McLeod gene, may develop symptoms of the latter.
Because of medical advances and stem cell treatment this condition no longer seriously shortens the lives of those affected. If, however, their gene deletions also reach over into the McLeod gene they will most likely develop the latter condition's complications, and these patients must therefore also be closely monitored.
In a larger series of German McLeod patients, currently being written up by Dr. Kevin Peikert, previously in Dresden (where he was one of the organizers of the 9th International NA symposium), now Rostock, one or two of these patients will also be described.
A major practical problem for McLeod patients in Germany in general concerns the issue of banking their blood donations for the future use of themselves or of others affected by the syndrome. Through contacts with health insurers and with a small number of specialized blood banks we hope to solve the practical, mainly monetary and administrative issues of long-term storage and availability of such rare blood group preserves.
Prof. Danek's presentation was very well received and it may be predicted that an even larger number of McLeod cases will be identified in the near future. Both practical aspects as well as the enigmatic relationship to chorea-acanthocytosis will hopefully receive more attention and eventually may lead to a full understanding of both of these neuroacanthocytosis syndromes.