Inflammation
Hormonal Imbalance
Neoplasia
More commonly associated with an autosomal dominant gene inheritance
Multi-system syndromes: Zimmerman-Laband syndrome, Jones syndrome, Ramon syndrome, Rutherford syndrome, juvenile hyaline fibromatosis, systemic infantile hyalinosis, and mannosidosis
Some unknown causes

Mechanism
Genetic linkage studies are among the most popular methods of study to look at the mechanism of this HGF. Genetic linkage studies have found to localize genetic loci for autosomal dominant forms of HGF to chromosome 2p21-p22 (indicative of HGF1) and chromosome 5q13-q22 (indicative of HGF2). Chromosome 2p21-p22 has been refined to an interval of ~2.3 Mb to construct an integrated physical and genetic map of the 16 genes interval. Here, a mutation is found in sequencing these 16 genes.There is an insertion of a cytosine between nucleotides 126,142 and 126,143 in codon 1083 of the SOS1 gene, meaning there is a mutation in SOS1. This causes a problem because SOS1 introduces a frameshift mutation and creates a premature stop codon. Also, it can segregate over generations, most commonly four. Once it causes a premature stop codon, the chromosome loses four important proline-rich SH-3 binding domains in the carboxyl-terminal region of the SOS1 protein. As a result, the N-terminal amino acids for SOS1 is fused into a 22–amino acid carboxyl terminus. Researchers claim that this mutation in the SOS1 gene is a probable primary cause of this disease but limited information supports the mechanism of this claim. Diagnosis
There are very few ways to test a patient for HGF. Currently, the most common way to diagnose a patient is by means of a physical evaluation.
The patient can also experience damage or loss of teeth. Obvious signs
Most obvious sign is gingival overgrowth (overgrowth of the gums)
Hindered chewing efficiency and difficulties eating
Increasing mobility of teeth
Abnormally shaped teeth and abnormal movement of teeth
Inflammation and/or swelling of the gums/gingiva
Not necessarily any signs of pain but experiencing pain is possible
Difficulties in speaking, oftentimes can lead to speech disorders
Other dental and oral problems
In some cases, Hereditary Gingival Fibromatosis may cause bleeding from the gums, or gum ulcerations. Cause
Though much more research needs to be done, researchers have mostly agreed that a mutation in SOS1, son-of-sevenless gene, is responsible for this disease. SOS1 is a guanine nucleotide-exchange factor that functions in the transduction of signals that control cell growth and differentiation. A mutation in the SOS1 gene results in a single nucleotide insertion. Specific linkage studies have localized the mutation for isolated, nonsyndromic autosomal dominant forms of gingival fibromatosis to chromosomes 2 and 5, more specifically 2p21-p22 and 5q13-q22. Genetic
HGF1 - Caused by a mutation in the SOS1 gene localized on chromosome 2p21-p22HGF2 - Caused by a mutation in the SOS1 gene localized on chromosome 5q13-q22Mutations in the RE1-silencing transcription factor (REST) gene can also cause this syndrome. Non genetic
HGF may also be caused by unwanted side effects of pharmacological agents like phenytoin, ciclosporin, and some calcium-channel blockers, meaning HGF is a disease that can be drug-induced. However, there is little next to no research done in this area to support the claim.