Hort Tandem Repeat (STR) testing, often used in forensic science and genetic analysis, is a powerful tool for identifying individuals based on the number of repeating units at specific locations in their DNA. STR testing can still identify someone with a germ-line mutation by detecting changes in the repeat patterns at specific DNA loci. If a germ-line mutation alters an STR region, the individual’s STR profile may show a new allele or a different number of repeats than expected based on their relatives. This can result in mismatches in parent-child STR profiles, which might indicate a mutation. While STR testing is generally reliable, the results must be carefully interpreted.

https://www.researchgate.net/publication/383411024_Genetic_Individuality

This is already possible based on how we do STR-based DNA fingerprinting. There is even an established protocol for reporting new variants.

I use this as a lesson with my genetics students - gives them a better understanding of where new alleles come from.