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Library of Medicine®| Hereditary diffuse leukoencephalopathy
with spheroids (often shortened to HDLS) On this page: Reviewed
December 2012 What is HDLS? Hereditary diffuse
leukoencephalopathy with spheroids (HDLS) is a neurological
condition characterized by changes to certain areas of the
brain. A hallmark of HDLS is leukoencephalopathy, which is
damage to a type of brain tissue called white matter. White
matter consists of nerve fibers (axons) covered by a substance
called myelin that insulates and protects the nerves. Areas of
damage to this brain tissue (white matter lesions) can be seen
with magnetic resonance imaging (MRI). Also common in HDLS are
swellings called spheroids in the axons of the brain, which are
a sign of axon damage. Damage to myelin and axons is thought to
contribute to many of the neurological signs and symptoms in
people with HDLS. Symptoms of HDLS usually begin in a person's
forties and worsen over time. Personality changes, i