I seem to remember he wasn't a musical prodigy or anything. That was Mozart.

Beethoven had his father practice music day in and day out, and then beat the shit out of him if he wasn't perfect. I think injuries from his father's abuse have been attributed to his hearing loss later in life.

genome-wide association study (GWAS) of musical talent. However, a subsequent GWAS involving 606,825 individuals identified the specific locations (loci) of 69 genes significantly associated with beat synchronization ability, assessed by the question: Can you clap in time with a musical beat? A follow-up family study showed that polygenic indices had a small but significant effect on several music-related skills and traits.

An important thing to remember is the term "significant" and its use in studies. In studies, the word does not mean "major" or "very important" but instead means, essentially, "does whatever we're looking at have a role in the outcome, and we're not looking at random chance here". It's just an issue of statistics.

So what they did was look at the genomes for 600k+ people, looked for associations with people with musical talent, and identified a 'beat synchronization' gene. Those who have it have a more innate ability to keep a musical beat than those who don't, which has a small influence in a person's musical ability.

However, this also seems to be something a person can compensate for. Such as, as Beethoven did, practice music a whole ton and brute forced the learning curve.