BODY FLUIDS AND EFFECT OF HEREDITARY DISORDERS 213 
reactions, to other derivatives all of which, having a high renal clearance, are readily 
excreted in the urine. However, phenylalanine itself is almost all reabsorbed by the 
kidney tubule and so cannot be excreted in sufficient amounts to lower the plasma 
level to normal limits. This can only be done by limiting the intake of phenylalanine 
in the diet. There are certain other biochemical abnormalities associated with the 
disease which have yet to be explained, one of which is the reason for an apparent 
disturbance of tryptophane metabolism leading to an increased urinary excretion of 
indolylacetic acid and indolyllactic acid. 
TY 
TAU 
THR 

® 

HIS 
Ly 
GLU-NIi, 
Clu 
ARG 
LYS 
Fig. 14. A paper chromatogram of the blood plasma from the maple-syrup-urine disease case. 
Maple-syrup-urine disease. In 1954, MENKES, HURST AND CraiG”™ described a family 
in which four out of six children were severely affected with neurological disturbances 
and failed to survive longer than a few months. They drew attention to the fact that 
the urine of the children had a strange smell like that of maple syrup. In 1958, WESTALL, 
Dancis, MILLER AND LEvitz*® reported a further case and showed that the urine 
contained abnormally high amounts of the branched chain animo acids leucine, 
isoleucine and valine (Fig. 13). The plasma levels of these amino acids were also 
markedly elevated (Fig. 14) as also was the level of methionine whilst the cystine 
References p. 217/219 
