Astoria may have Fanconi. I have a basenji, Lacan, with the same symptoms (polyuria and polydipsis), as I had already read about Fanconi syndrome, I went straight to the vet and had the tests that confirmed the diagnosis. You don't need to do the DNA test anymore, because Astoria already has the symptoms, you just need to confirm it, unfortunately I have to say that. I have attached Dr. Gonto's protocol, which is on the Basenjis Companions website, which is what we should do, with the assistance of a vet who reads the protocol! The sooner we start, the better results, because we can avoid getting worse, since the syndrome has no cure, but we can help our dear Basenjis to live longer and regular lives.
i hope you have already found a vet to help you.
Please read the file with the protocol that will clarify a lot of things for you. Dr Gonto is an american doctor and everyone says he is open to vet contacts. His protocol has been used for about 30 years and i recently read a masters thesis on fanconi and the use of the protocol - she concludes that it is the best, in fact, the only treatment that works.
We started the treatment 1 or 2 months ago, then we will do new tests to see how the treatment is going and regulate the dose of bicarbonate tabs. I wish you good luck, patience and much love to do the best you can.