[Modulation of the phenotypic expression in the patient with cystinuria: influence of therapeutic intervention and diet].
OBJECTIVE
The final phenotype of patients with cystinuria depends on the absence or molecular defect, more or less acute, of the transport of cystine and dibasic aminoacids, and, also on environmental factors. The objective of this work is to study the effect of the modulation of some environmental factors (urinary pH, intake of liquids, pharmacological treatment and, specially, diet) on the final phenotype of the patient with cystinuria.


METHODS
We study 45 patients with cystinuria (25 men and 20 women), 42 relatives (15 men and 27 women) and 90 unrelated controls. Anthropometric, clinical (personal and familiar history of urinary infections, colics and calculi expulsion), biochemical (microscopy analysis of urine and urinary aminoacids cuantification) and life style (diet and medical treatment) variables were obtained. Statistical analysis was performed using tests to compare means and frequencies and, also, logistic regression and multivariate analysis.


RESULTS
Of the 45 patients with cystinuria, only 20% showed cystine cristalls in urine, the rest of the phenotypical manifestations of cystinuria were found with the same prevalence as in relatives and in the control group. 50% of the patients did not undergo any therapeutic intervention; of these, only 50% were effective. In patients with cystinuria, the presence of cystine cristalls was associated with a diet rich in meats and poor in milk products (p < 0.05). Meat consumption also tend to associate with a higher risk of urinary infections, meanwhile the stone expulsion showed a negative tendance with a diet rich in phytate. The elevate consumption of oranges and mandarins was the variable of the diet which was more associated with urinary aminoacids concentrations, specially with lower levels of lysine and arginine (p < 0.05).


CONCLUSIONS
Some components of the diet, in addition to standard treatment, modulate the phenotypical manifestations of cystinuria.
Francés
Francesc
F
Unidad de Epidemiología Genética y Molecular, Facultad de Medicina, Universidad de Valencia, España. francesc.frances@uv.es
Corella
Dolores
D
Carrasco
Paula
P
Sáiz
Carmen
C
Guillén
Marisa
M
D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000652:urine; D002648:Child; D032084:Citrus sinensis; D003131:Combined Modality Therapy; D003553:Cystine / Q000032:analysis; D003555:Cystinuria / Q000150:complications / Q000178:diet therapy / Q000188:drug therapy / Q000378:metabolism / Q000628:therapy*; D003611:Dairy Products; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008019:Life Style; D008297:Male; D008460:Meat / Q000009:adverse effects; D008875:Middle Aged; D010641:Phenotype; D019357:Potassium Citrate / Q000627:therapeutic use; D017693:Sodium Bicarbonate / Q000627:therapeutic use; D011795:Surveys and Questionnaires; D014556:Urine / Q000737:chemistry; D052878:Urolithiasis / Q000209:etiology / Q000517:prevention & control
D000596:Amino Acids; D003553:Cystine; D017693:Sodium Bicarbonate; D019357:Potassium Citrate