Genetic testing can provide a definite diagnosis and identify thousands of different genetic variants associated with FH.
On a more advanced level, once you have done your genetic testing and you have your sequencing results, ClinVar is a powerful free tool to learn about your particular variant of FH. Visit ClinVar at http://www.ncbi.nlm.nih.gov/clinvar/ .
For example, my medical genomics report for FH DNA genetic testing concluded: I am Heterozygous for the nonsense c.1448G>A (p.Trp483p*) sequence variant in the LDLR gene. The report also said this previously reported LDLR gene variant is considered to be PATHOGENIC and confirms a diagnosis of FH.
My results itself indicate:
Variant detected: c.1488G>A
Predicted amino acid change: p.Trp483*
Alternative nomenclature: W462X
Therefore, I can use ClinVar by searching for my gene sequencing results. For example, I type in p.Trp483* at the search bar, and it brings me to a few matching results, and when I look for the c.1488G>A in these results, it brings me to the page: VCV000226356.27 - ClinVar - NCBI , which reconfirms my FH condition.