Subacute combined degeneration (SCD) is a rare neurological complication of vitamin B12 deficiency, characterized by demyelination of the dorsal and lateral spinal cord. Herein, we describe three cases, who presented with SCD, one related to reduced intake of vitamin B12 because of a vegetarian diet and two related to nitrous oxide exposure during surgery. MR images of our patients revealed symmetrical hyperintense signals in dorsal and lateral columns in T2 weighted series. After treatment with intramuscular B12 injections (1 mg daily for 2 weeks, once weekly thereafter for three months) all patients showed improvement of their symptoms. Abnormalities of the spinal cord on MRI resolved in three months. In conclusion, SCD either due to nitrous oxide exposure or due to reduced intake of vitamin B12 is a reversible condition, when detected and treated early.
Objective:
A rare variant in TREM2 (p.R47H, rs75932628) has been consistently reported to increase the risk for Alzheimer disease (AD), while mixed evidence has been reported for association of the variant with other neurodegenerative diseases. Here, we investigated the frequency of the R47H variant in a diverse and well-characterized multicenter neurodegenerative disease cohort.
Methods:
We examined the frequency of the R47H variant in a diverse neurodegenerative disease cohort, including a total of 3058 patients clinically diagnosed with AD, frontotemporal dementia spectrum syndromes, mild cognitive impairment, progressive supranuclear palsy syndrome, corticobasal syndrome, or amyotrophic lateral sclerosis and 5089 control subjects.
Results:
We observed a significant association between the R47H variant and AD, while no association was observed with any other neurodegenerative disease included in this study.
Conclusions:
Our results support the consensus that the R47H variant is significantly associated with AD. However, we did not find evidence for association of the R47H variant with other neurodegenerative diseases.
To our knowledge, this is the first Turkish family in which nine individuals in five generations are affected. We suggest an important effect of anticipation and genetic impact of the diseases and describe specific clinical features. Further investigation of clinical, genetic, and biochemical similarities between PLMS and RLS may yield important clues, adding to our understanding of the pathophysiology of these common diseases.
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