Summary
Phenylketonuria is a not uncommon cause of mental deficiency (there are probably 1600 cases in Great Britain alone). On the supposition that the high level of phenylalanine or its breakdown products in the blood and cerebrospinal fluid might be responsible for the mental retardation in this disorder we have treated a two year‐old child with a diet low in phenylalanine. The introduction of this diet was associated with an appreciable improvement in the patient's mental status and a fall in the level of phenylalanine in the blood and urine. When phenylalanine was again given in fairly large amounts there was an immediate and dramatic deterioration in the child's mental and biochemical condition. A similar phenylalanine intake produced no clinical reaction in a control child.
The main source of aminoacids in the diet was an acid casein hydrolysate which was specially treated to remove phenylalanine. The aim of the phenylalanine‐poor diet was to keep the phenylalanine blood level as near the normal range as possible. The preparation of such a diet presents little difficulty if a phenylalanine‐free casein hydrolysate is available. Its value in the treatment of other children is at present being investigated; it seems reasonable to assume that patients in the first two years of life will benefit most.
This case, which forms the basis of this paper, came under the observation of one of us during an investigation, by balance experiments, of the metabolism of atrophic infants. During life, the condition was diagnosed as one of congenital obliteration of the bile ducts, and it was thought that a study of the absorption and retention might prove useful in observing the effect of a low fat absorption on the absorption of calcium, phosphorus, carbohydrate and protein.The importance of disorders of fat digestion in producing infantile atrophy has been largely stressed by the German school, particularly by
Summary
Fourteen children suffering from cystine storage disease with aminoaciduria (Lignac‐Fanconi disease) have been studied i n the last 3 years, and the results are described in a series of eight papers of which this first paper contains a short review of the literature, some general remarks on aminoaciduria, cystinuria and cystine storage, and a brief statement on some of the results obtained and conclusions reached.
Publications by Lignac, Fanconi, Beuiner and Wepler, and others, as well as our own observations, lead us t o the conclusion that Lignac's disease (cystine storage disease) and Fanconi's syndrome of childhood (nephrotic glycosuric dwarfism) are one and the same disease. At the present time this disease cannot be identified with similar syndromes in which cystine storage has been excluded.
The variability of nearly every symptom in Lignac‐Fanconi disease is stressed. The most reliable diagnostic features besides dwarfing are cys tine storage and aminoaciduria of a characteristic pattern. Cystine storage can be demonstrated in vivo by slit‐lamp investigation in cornea and conjunctiva, as well as in bone marrow and lymph glands, and the cystine can be identified in biopsy material by microscopy, X‐ray crystallography and chromatography.
The aminoaciduria is accompanied by aminoacidaemia, and the characteristic pattern in urine is best shown by paper chromatography. The differentiation from other forms of aminoaciduria, such as that of newborn infants and classical cystinuria, is discussed.
Reasons are given why cystine storage and aminoaciduria are regarded as the result not of kidney dysfunction but of a prerenal disturbance of the whole aminoacid metabolism, probably situated within the reticulo‐endothelial system.
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