(•) STf.M': AM) (■) STIMRIA 591 



Because of its slight sohihility it appears as a deposit of hexagonal 

 crystals, and frequentlj'' forms cystine concretions (g. v.) in the urinary 

 bladder." According to Garrod it is more common than alkapto- 

 nuria, and, like the rest of the "Inborn Errors of Metabolism," occurs 

 much more often in males than in females. Hofmann**** was able to 

 collect from the literature to 1907 a total of 175 cases, of which 

 85 were males and 45 females. Baumann and others observed 

 that in cystinuria the urine often contains, besides the cystine, the 

 diamines cadavcrine and pntrescine, which are formed from lysine 

 and ornithine respectively in the intestines through putrefaction, 

 and they naturally suspected that cystine arose in the same way. 

 Another view was that the diamines interfered with the oxidation 

 of sulphur in the body, so that it was eliminated in the unoxidized 

 form of cystine. But it has been demonstrated that neither of these 

 hypotheses is correct, for (1) cystine could not be found in the feces; 

 (2) if given by mouth, it is completely oxidized, and causes only the 

 appearance of excessive amounts of sulphates in the urine; (3) cys- 

 tinuria has been observed to occur independent of the presence of 

 the diamines, and not to be modified or caused by their administration 

 or pathological formation. The view now prevalent is that the cystine 

 that escapes in the urine in cystinuria is not derived from intestinal 

 putrefaction, but is formed in the tissues from the protein molecule, 

 and fails to be further decomposed because of some anomaly of metab- 

 olism. This view is supported by the fact that cystinuria often ap- 

 pears to be an hereditary disease, occurring in families for several 

 generations, it is independent of the diet, cystine appearing even if 

 proteins are withheld, and also independent of intestinal putrefac- 

 tion.^^ It having been found that leucine and tyrosine may also occur 

 in the urine in cystinuria,^*' it seems probable that this condition de- 

 pends upon a general abnormality of protein metabolism. The rela- 

 tion of the diamines to the condition is, however, very uncertain. 

 Cystine does not seem to exert any toxic effect, and patients with 

 cystinuria do not usually appear to suffer greatly from the abnormal 

 metabolism, the chief trouble observed being due to the formation of 

 the concretions in the bladder.^^ Sometimes in children, however, 

 emaciation and earl}^ death without other apparent cause, have been 

 observed, and may be due to the metabolic anomaly. 



The metabolic error in cystinuria is not complete, for only a por- 

 tion of the total cystine of the catabolized proteins is excreted as 



*' Abderhalden (Zeit. physiol. Chem., 1903 (38), 557) has described a case in 

 a child in which the organs were infiltrated with masses of the cystine crystals. 



88 Cent. Grenz. Med. u. Chir., 1907 (10), 721. 



83 An isolated case of transient cystinuria in a patient with Raynaud's disease 

 is described bv Githens (Penn. IMed. Jour., 1910 (1), .507). 



90 See Abderhalden, Zeit. physiol. Chem.. 1919 (104). 129. 



91 This may be avoided by decreasing the cystine by means of a low protein 

 diet, and increasing its solubilitj' bv keeping the reaction of the urine alkaline 

 (Smillie, Arch. Int. Med., 1915 (16), 503). 



