Objective: To describe a new XK deletion associated with McLeod syndrome.

Background: McLeod syndrome is a rare genetic syndrome characterized by the association of chorea and acanthocytosis. This syndrome is an X-linked disease caused by hemizygous mutation or deletion in XK gene. To date, 37 disease-causing variants in the XK gene have been reported, including 26 mutations and 11 chromosome Xp21 deletions.

Methods: A 58-years old man without familial history was admitted in our Neurology Department for progressive chorea. He presented with diffuse chorea without facial involvement and a moderate dysarthria. His family noticed a recent irritability. Brain MRI revealed a bilateral and symmetrical frontal ventricular corn dilatation. Neuropsychological evaluation showed a moderate dysexecutive syndrome.

Results: Genetic analysis revealed absence of HTT gene expansion and VPC13A gene mutation. On biological examination, patient presented with acanthocytosis, elevated blood CPK and Kell antigen negative. Molecular studies including PCR and array CGH study allowed us to identify a new 3Mb deletion in Xp21 chromosome and diagnose a McLeod syndrome in our patient. Interestingly, the patient did not present with cardiac disorder. On electromyography, an asymptomatic axonal sensitive and motor polyneuropathy was observed.

Conclusions: McLeod syndrome is a rare X-linked chorea associated with acanthocytosis. To date, only 12 chromosome Xp21 deletions (including this case) has been identified. 4/12 deletions were clinically characterized by Xp21 contiguous gene syndrome with a deletion of multiple gene loci that are adjacent to XK gene, as DMD (Duchenne and Becker muscular dystrophy), CYBB (X-linked chronic granulomatous disease) and/or RPGR (Retinitis pigmentosa-3) genes. Molecular studies for McLeod syndrome were set up in our hospital allowing familial study and genetic counselling to the family of our patient.

References: Mengfatt Ho, Jamel Chelly, Nick Carter, Adrian Danek, Paul Crocker, Anthony P. Monaco. Isolation of the gene for McLeod syndrome that encodes a novel membrane transport protein. Cel. 1994. 77: 869-80.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/new-xk-deletion-associated-with-mcleod-syndrome/