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Title
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Mutations in the **SPTLC2** subunit of serine palmitoyltransferase cause hereditary sensory and autonomic neuropathy type I
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Author
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Abstract
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| Hereditary sensory and autonomic neuropathy type I (HSAN-I) is an axonal peripheral neuropathy associated with progressive distal sensory loss and severe ulcerations. Mutations in the first subunit of the enzyme serine palmitoyltransferase (SPT) have been associated with HSAN-I. The SPT enzyme catalyzes the first and rate-limiting step in the de novo sphingolipid synthesis pathway. However, different studies suggest the implication of other genes in the pathology of HSAN-I. Therefore, we screened the two other known subunits of SPT, SPTLC2 and SPTLC3, in a cohort of 78 HSAN patients. No mutations were found in SPTLC3, but we identified three heterozygous missense mutations in the SPTLC2 subunit of SPT in four families presenting with a typical HSAN-I phenotype. We demonstrate that these mutations result in a partial to complete loss of SPT activity in vitro and in vivo. Moreover, they cause the accumulation of the atypical and neurotoxic sphingoid metabolite 1-deoxy-sphinganine. Our findings extend the genetic heterogeneity in HSAN-I and enlarge the group of HSAN neuropathies associated with SPT defects. We further show that HSAN-I is consistently associated with an increased formation of the neurotoxic 1-deoxysphinganine, suggesting a common pathomechanism for HSAN-I. |
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Language
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English
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Source (journal)
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The American journal of human genetics / American Society of Human Genetics [Bethesda, Md] - New York, N.Y., 1949, currens
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Publication
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New York, N.Y.
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2010
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ISSN
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0002-9297
[print]
1537-6605
[online]
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DOI
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10.1016/J.AJHG.2010.09.010
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Volume/pages
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87
:4
(2010)
, p. 513-522
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ISI
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000283037600007
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Full text (Publisher's DOI)
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Full text (open access)
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