ribosome binding protein 1) gene, CALU (calumenin) gene, CTNNB1 (catenin beta 1) gene, MIR22HG (produces the MIR22HG long non-coding RNA) gene, SPARC (secreted protein acidic and cysteine rich [also termed osteonectin]) gene, THBS2 (thrombospondin-2) gene, COL6A2 (collagen type VI alpha 2 chain) gene, SEC31A {SEC31 homolog A, COPII coat complex component) gene, EIF5A (eukaryotic translation initiation factor 5A) gene, COL1A1 (collagen type I alpha 1 chain) gene, COL1A2 (collagen type I alpha 2 chain) gene, COL3A1 (collagen type III alpha 1 chain) gene, PAFAH1B1 (platelet activating factor acetylhydrolase 1b regulatory subunit 1) gene, SERPINH1 (serpin family H member 1) gene which produces heat shock protein 47, PDLIM7 (PDZ and LIM domain protein 7) gene, and MYL12A (myosin regulatory light chain 12A) gene. While very few cases have been analyzed to date, USP6-containing fusion genes have been found in the tumor cells of 7 of 15 tested cases of cranial fasciitis and six of  six tested cases of intravascular fasciitis.All of the USP6-containing fusion genes in NF and variants overproduce a chimeric protein containing a part of the USP6 genes product, ubiquitin carboxyl-terminal hydrolase 6a, that has uncontrolled deubiquitinating enzyme activity. This may result in the inappropriate stimulation of  multiple cell signaling pathways including the Wnt signaling pathway, one of the JAK-STAT signaling pathways (i.e. the Jak1-STAT3 pathway), the c-Jun signaling pathway, and the NF-κB signaling pathway. Each of these pathways, when inappropriately activated, has been implicated in promoting the development of various tumors and cancers.
The SCN9A gene instructs the production of the alpha subunit for the NaV1.7 sodium channel and the SCN10A gene instructs the production of the alpha subunit for the NaV1.8 sodium channel. Sodium channels transport positively charged sodium atoms (sodium ions) into cells and play a key role in a cells ability to generate and transmit electrical signals. The NaV1.7 and NaV1.8 sodium channels are found in nerve cells called nociceptors that transmit pain signals to the spinal cord and brain. The SCN9A gene mutations that cause small fiber neuropathy result in NaV1.7 sodium channels that do not close completely when the channel is turned off. Many SCN10A gene mutations result in NaV1.8 sodium channels that open more easily than usual. The altered channels allow sodium ions to flow abnormally into nociceptors. This increase in sodium ions enhances transmission of pain signals, causing individuals to be more sensitive to stimulation that might otherwise not cause pain. In this condition, the small fibers that extend from the nociceptors through which pain signals are transmitted (axons) degenerate over time. The cause of this degeneration is unknown, but it likely accounts for signs and symptoms such as the loss of temperature differentiation and pinprick sensation. The combination of increased pain signaling and degeneration of pain-transmitting fibers leads to a variable condition with signs and symptoms that can change over time. SCN9A gene mutations have been found in approximately 30 percent of individuals with small fiber neuropathy; SCN10A gene mutations are responsible for about 5 percent of cases.