It's not just direct metabolism of stuff in the diet. Your body indirectly makes stuff that is then metabolized into uric acid (e.g. your DNA). Could be making too much, could not be excreting enough.
"Many factors contribute to hyperuricemia, including genetics, insulin resistance, iron overload, hypertension, hypothyroidism, chronic kidney disease, obesity, diet, use of diuretics (e.g. thiazides, loop diuretics), and excessive consumption of alcoholic beverages. Of these, alcohol consumption is the most important."
"Causes of hyperuricemia can be classified into three functional types: increased production of uric acid, decreased excretion of uric acid, and mixed type. Causes of increased production include high levels of purine in the diet and increased purine metabolism. Causes of decreased excretion include kidney disease, certain drugs, and competition for excretion between uric acid and other molecules. Mixed causes include high levels of alcohol and/or fructose in the diet, and starvation."
https://en.wikipedia.org/wiki/Hyperuricemia#Increased_produc...
Purines and pyrimidines make up the two groups of nitrogenous bases, including the two groups of nucleotide bases. Two of the four deoxyribonucleotides (deoxyadenosine and deoxyguanosine) and two of the four ribonucleotides (adenosine, or AMP, and guanosine, or GMP), the respective building blocks of DNA and RNA, are purines.
https://en.wikipedia.org/wiki/Purine
Could just be a bad roll of the genetic dice with a dash of lifestyle.