McLeod syndrome, also known as McLeod phenomenon is a rare X-linked syndrome caused by a mutation in the XK gene that results in haematological abnormalities and late-onset, slowly progressive degeneration of a variety of tissues including the brain, peripheral nerves, muscle and heart 1. It should not be confused with Swyer-James-MacLeod syndrome (post-infectious obstructive bronchiolitis).
MRI shows increased T2 signal in the lateral putamen with caudate atrophy and secondary lateral ventricular dilation 2. There is neuronal loss with secondary gliosis in the caudate and globus pallidus. Similar changes may also be seen in the thalamus, substantia nigra and putamen. The cerebellum and cerebral cortex are generally spared.
History and etymology
McLeod syndrome was first described in 1961 after a Harvard dental student (Hugh McLeod) was discovered to have abnormal red blood cells following routine blood donation. Subsequent analysis showed weak expression of Kell system antigens and acanthocytosis at microscopy.