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The official name of this gene is “serine palmitoyltransferase, long chain base subunit 1.”
SPTLC1 is the gene's official symbol. The SPTLC1 gene is also known by other names, listed below.
The SPTLC1 gene provides instructions for making one part (subunit) of an enzyme called serine palmitoyltransferase (SPT). The SPT enzyme is involved in making certain fats called sphingolipids. Sphingolipids are important components of cell membranes and play a role in many cell functions. The SPT enzyme, which is made up of three subunits, initiates the first step of sphingolipid production. Specifically, the enzyme combines the molecules serine and palmitoyl CoA to form a molecule called ketodihydrosphingosine. A series of additional chemical reactions produce sphingolipids. Within the cell, the SPT enzyme is mainly found on the endoplasmic reticulum, which is a structure involved in protein processing and transport.
At least three mutations in the SPTLC1 gene have been found to cause hereditary sensory neuropathy type 1. These mutations change single protein building blocks (amino acids) in the SPTLC1 subunit. One mutation that has been seen in multiple affected families replaces the amino acid cysteine with the amino acid tryptophan at position 133 in the SPTLC1 subunit (written as Cys133Trp or C133W).
Altered SPTLC1 subunits can still be used to build SPT, but the resulting enzyme is nonfunctional. A lack of functional SPT enzyme leads to a decrease in sphingolipid production and a harmful buildup of certain byproducts. Sphingolipids are found in myelin, which is the covering that protects nerves and promotes the efficient transmission of nerve impulses. A decrease in sphingolipids disrupts the formation of myelin, causing nerve cells to become less efficient and eventually die. When sphingolipids are not made, an accumulation of toxic byproducts can also lead to nerve cell death. This gradual destruction of nerve cells results in loss of sensation and muscle weakness in people with hereditary sensory neuropathy type 1.
Cytogenetic Location: 9q22.2
Molecular Location on chromosome 9: base pairs 92,031,133 to 92,115,473
The SPTLC1 gene is located on the long (q) arm of chromosome 9 at position 22.2.
More precisely, the SPTLC1 gene is located from base pair 92,031,133 to base pair 92,115,473 on chromosome 9.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about SPTLC1 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
acids ; amino acid ; cell ; CoA ; cysteine ; endoplasmic reticulum ; enzyme ; gene ; hereditary ; molecule ; mutation ; nerve cell ; neuropathy ; protein ; sensory neuropathy ; serine ; subunit ; toxic ; transferase ; tryptophan
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.