Here I present: “Xanthinuria”, Victor McKusick, Mendelian Inheritance in Man’, 1966. 黄原尿症。(XAN).
INTRODUCTION.
Xanthinuria is a genetic disorder causing the accumulation of xanthine. It is caused by a deficiency of the enzyme xanthine dehydrogenase.
Xanthinuria, which was first described in 1954 by Dent and Philpot is characterized by excretion of large amounts of xanthine in the urine and a tendency to form xanthine stones. Uric acid is strikingly diminished in serum and urine. Two (2) clinically similar but distinct forms of xanthinuria are recognized. In type-I (XAN1) there is an isolated deficiency of xanthine dehydrogenase, and in type-II (XAN2) there is a dual deficiency of xanthine dehydrogenase and aldehyde oxidase.
There is evidence that Xanthinuria type-1 is caused by a mutation in the xanthine dehydrogenase (Enzyme Commission number EC# 1.17.3.2) gene (XDH) on cytogenetic location 2p23.1 and genomic coordinates 2:31,334,321-31,414,742. The screenshot of the XDH gene 80,422 bp (base pairs) of DNA sequence length is shown BELOW. Nine (9) other genes besides XDH are listed BENEATH.
| Coordinate | Symbol | Genomic Name. |
| 2:30,722,771 | CAPN13 | Calpain 13 |
| 2:30,886,782 | GALNT14 | GALNT14 |
| 2:31,173,056 | CAPN14 | Calpain 14 |
| 2:31,234,152 | EHD3 | EH domain-containing 3 |
| 2:31,334,321 | XDH | Xanthine dehydrogenase (xanthine oxidase) |
| 2:31,522,480 | SRD5A2 | Steroid-5-reductase, alpha polypeptide-2 |
| 2:31,800,001 | CANDF1 | Candidiasis, familial, 1 |
| 2:31,867,823 | MEMO1 | Mediator of cell motility 1 |
| 2:32,011,649 | DPY30 | DPY30 histone methyltransferase complex |
| 2:32,063,556 | SPAST | Spastin |
