Mental retardation and ataxia due to normotriglyceridemic hypobetalipoproteinemia.
A 12-year-old boy with mental retardation, obesity, ataxia, and visual impairment was shown to have normal fasting plasma triglyceride but low cholesterol and vitamin E levels. Investigations indicated that he was compound heterozygous for two mutations in the apolipoprotein B gene (APOB), resulting in a failure to express apolipoprotein B-100, yet retain apolipoprotein B-48 production. The proband therefore was able to form chylomicrons, but not a low-density lipoprotein capable of receptor-mediated endocytosis. This resulted in chronic vitamin E deficiency. We suggest the term normotriglyceridemic hypobetalipoproteinemia for this easily recognizable condition.
Molecular Pathology Laboratory, Canterbury Health Laboratories, Christchurch, New Zealand.
Vivienne M
VM
Homer
Peter M
PM
George
Stephen
S
du Toit
James S
JS
Davidson
Callum J
CJ
Wilson
D001055:Apolipoproteins B / Q000097:blood / Q000235:genetics*; D001259:Ataxia / Q000209:etiology*; D015153:Blotting, Western; D002648:Child; D002675:Child, Preschool; D008078:Cholesterol, LDL / Q000097:blood; D002914:Chylomicrons; D006801:Humans; D006995:Hypobetalipoproteinemias / Q000150:complications* / Q000235:genetics*; D007223:Infant; D008607:Intellectual Disability / Q000209:etiology*; D008297:Male; D009154:Mutation; D009765:Obesity / Q000209:etiology; D016133:Polymerase Chain Reaction; D014280:Triglycerides / Q000097:blood; D014810:Vitamin E / Q000097:blood
D001055:Apolipoproteins B; D008078:Cholesterol, LDL; D002914:Chylomicrons; D014280:Triglycerides; D014810:Vitamin E