Human biochemical genetics / by H. Harris.

  • Harris, Harry, 1919-1994.
Date:
1966
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Human biochemical genetics / by H. Harris. Source: Wellcome Collection.

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    PHENYLKETONURIA 49 two- and four-hourly intervals after feeding a standard dose of L-phenylalanine the heterozygotes show a phenylalanine level of about twice that of the controls at each period (43). The most plausible interpretation of the results is that the heterozygotes, as a group, have significantly less than the normal amount of phenylalanine hydroxylating enzyme activity. Table 10. Mean plasma phenylalanine concentration in parents of Phenylketonurie patients and in controls, in the fasting state and after the administration of a standard dose of phenylalanine. {After Hsia, et al. 1956) Plasma phenylalanine conc. /¿м/т1. , л , Parents of Controls Phenylketonurie patients (0-1 g./kg. body weight) Alkaptonuria Alkaptonuria is readily recognised by the characteristic changes in colour which occur in the urine. The urine when freshly passed is normal in appearance but if left to stand it soon begins to darken. Alkalinity speeds up the change and the urine passes through a series of shades of brown and finally may appear quite black. Linen and woollen fabrics moistened with the urine become darkly stained and as a result the condition is frequently recognised in early infancy by the characteristic staining of the napkins. On other occasions the abnormality is detected for the first time in the course of a life- insurance examination or a routine medical investigation when the urine is found to have strongly reducing properties, and then its other peculiar characteristics are noted. These curious properties of the urine persist unchanged throughout life. In other respects the affected individuals appear quite healthy, except as they grow older their ligaments and cartilages tend to become darkened and they are particularly prone to develop a form of osteoarthritis which may be quite severe. These changes are called ochronosis.