Concentrations of purine bases in soybean-derived food and in some Japanese food were quantitatively determined with the use of high-performance liquid chromatography (HPLC). After hydrolyzation with 70% perchloric acid, each of the bases, adenine, guanine, hypoxanthine and xanthine were determined. Total purine bodies were calculated by the sum of each of the purine bases. Concentrations of purine bodies were as follows: food derived from soybeans: 21.9 - 63.5 mg/100g or 100mL; purine-rich vegetables: 39.1 - 171.8 mg/100g; beers: 0.18 - 8.26mg/100mL; Japanese snacks: 14.1 - 159.3 mg/ 100g or 100mL. It is recommended that the amount of dietary purine bodies consumed by a gouty or hyperuricemic patient be limited to 400 mg per day. Although purine concentrations in the food reported here did not exceed 200 mg/100g, overeating should be avoided and good dietary habits are commendable.
Whether the number of patients with hyperuricemia or gout has continued to increase in Japan since 2000was investigated by reviewing the results of comprehensive medical examinations conducted in Tokyo and the results of a patient survey conducted by the Ministry of Health, Labor and Welfare of Japan. According to the 2001 National Livelihood Survey encompassing the entire population, the number of gout patients was estimated at 696,000, but the number of newly affected male patients decreased. Further, according to a survey of medical institutions, the number of gout patients peaked at 14,200 in 1996and decreased to 11,000 in 2002. Regarding the frequency of hyperuricemia in men, on a comparison of health screenings conducted in 1999 and 2003 at the Itabashi Chuo Medical Examination Center, the frequency of serum uric acid level≥7.0mg/dl decreased from 22.6% to 21.5%, and the frequency of hyperuricemia was decreased in all age groups except for men in their 20's. Men in their 30's-50's are most likely to be affected by life habits. On a comparison of health screenings conducted in 1995 at Tokyo Jikei Hospital, the frequency of hyperuricemia had decreased slightly to 20.9% in 2003. However, the frequency of complications such as obesity, abnormal glucose tolerance and hypertension increased, suggesting that decreases in hyperuricemia after 2000may be concealed by the increased numbers of diabetes patients as the frequency of obesity continues to rise.
We performed mutational analysis in three patients suggestive of familial juvenile hyperuricemic nephropathy (FJHN), examininga ll coding exons of the uromodulin (UMOD) gene by exon PCR and direct sequencing of the exon PCR products. In family M, a single nucleotide substitution(c.860G>A) was found in exon 4, resulting in the amino acid change from cysteine to tyrosine at codon 287 (C287Y). In family Y, c.890G>C mutation was detected in exon 5, causing the amino acid change C297S. None of these mutations was found in family I. UMOD contains four epidermal growth factor (EGF)-like domains that are predicted to mediate protein-protein interaction and maintain the tertiary structure of the UMOD protein. Two previously undescribed mutations, C287Y and C297S, are located within the fourth EGF-like domain. We suggest that replacement of the cysteine residue, which stabilizes the native domain fold by a disulfide bond, affects the function of UMOD, resulting in the development of FJHN.
The increasing proportion of patients showing a family history and renal insufficiency in gout suggests that genes for gout may be closely linked with familial juvenile hyperuricemic nephropathy (FJHN), especially for those with precocious onset of gouty attack. This study investigated the clinical features of juvenile gout as well as its possible association with FJHN. A total of 543 cases of juvenile gout with onset of gouty attack earlier than 20 years of age listed in the Hoping Gout Database were enrolled, and 5,269 gouty cases with the onset age between 40 to 50 years were selected as control group. The body weight, height and body mass index in juvenile gout were significantly higher than those in the control group (P<0.0001). The number of joints involved and the percentages of hypertension, diabetes, hyperlipidemia and nephrolithiasis in juvenile gout were significantly lower than those in the control group (P<0.0001). There was no significant difference in the percentage of female gout and tophaceous gout between the two groups. Serum orate level,24-hour urinary uric acid excretion and creatinine clearance in juvenile gout were significantly higher than those in the control group (P<0.0001). The percentage of renal insufficiency in juvenile gout was only 9.8% and was significantly lower than that in the control group (P<0.0001). The percentage of familial aggregation in juvenile gout was about 1.9-fold higher than that in control group (44.3% vs.23.8%, P<0.0001). Among patients with a family history juvenile gout shows a significantly higher proportion of heritage from the father (P<0.0001) and a significant lower proportion of heritage from the sibs and mother than the control group (P<0.0001 for both). In conclusion, juvenile gout is associated with both excessive weight and hereditary background, while the FJHN gene may not be the main gene responsible for juvenile gout in Taiwan.