Update of the original HDLS kindred: divergent clinical courses

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) was first identified among a Swedish kindred with 17 cases. The average age of onset was 36 years. Autopsy in four cases revealed the presence of axonal spheroids. The causative gene is unknown.

We performed genealogical and longitudinal observations of the original kindred. Forty members were examined, five telephone-interviewed, and one of the original HDLS cases from 1984 was neuropathologically examined. The clinical course was documented. The cerebrospinal fluid (CSF) findings of two recently affected cases were examined, and one of those autopsied.

Of those examined, two developed HDLS during our survey and 38 were healthy. Those interviewed by telephone were healthy. One had symptoms suggestive of HDLS in 1984, but autopsy during our survey showed no spheroids. This patient, two relatives healthy at our examination and one without symptoms at telephone interview had HDLS diagnoses in the 1984 report. Thus, four HDLS diagnoses were unconfirmed. The number of identified patients amounts to 15 among 75 individuals in four generations, including two recent cases who demonstrated a subacute multisystem encephalopathy in Case 1 and an insidious course in Case 2. CSF showed signs of neurodegeneration without inflammation, and autopsy verified HDLS in Case 1.

Some HDLS cases were misdiagnosed with unspecified psychiatric diagnoses in affected relatives from the original 1984 publication. However, HDLS is an encephalopathy dominated by a frontal lobe syndrome with an inexorably progressive and fatal course, where the different symptomatology in two recent cases confirmed the existence of acute and chronic variants.