DEKARBOKSILAZNY INSUFFICIENCY (synonym Menkesa disease) — the hereditary disease caused by disturbance of exchange of amino acids with a branched chain (valine, a leucine and from a leucine) and characterized by the progressing defeat of c. N of page.
It is for the first time described an amer. pediatricians Menkes (J. N of Menkes) et al. (1954), then Westall et al. (1957) which showed that diseases are the cornerstone of disturbance of exchange of amino acids. Of N meets seldom, frequency in population makes 1 — 3: 100 000. A mode of inheritance autosomal and recessive (see. Inheritance ).
An etiology and a pathogeny
Development of a disease is connected with existence of the euzymatic block in cells in processes of decarboxylation of valine, a leucine, an isoleucine owing to what the specified amino acids collect in large numbers in blood, urine, cerebrospinal liquid. As a result of deamination of amino acids with a branched chain in biol, liquids concentration of alpha ketonic acids (isovalerianic, beta and methylvalerian, isokapron) which give to urine a specific smell of maple syrup increases.
The pathoanatomical picture
the Pathoanatomical picture is not specific. At the same time cirrhosis, dystrophic changes in renal tubules and a hypertrophy of pancreatic islands (Langergans) can be found.
A clinical picture
the First symptoms of a disease are found on 3 — the 5th day of life of the child. Children lose appetite, refuse to eat food, sometimes it is necessary to feed them via the probe. Vomiting and vomiting are observed. Further symptoms come to light nevrol: decrease in tendon jerks, lack of a reflex of Moro (see. Newborn ), the muscle tone raises. The child becomes uneasy, cries quietly. Within a week the tone of muscles raises, noted a pulling and crossing of the lower extremities, an opisthotonos, the general spasms, disorder of breath and cyanosis. The characteristic smell of urine appears at the end of the first week, sometimes earlier. If the child does not perish in the first weeks of life, then lag in weight, a delay of psychomotor development is noted further, it is frequent in combination with heavy nevrol, symptoms: spasms, opisthotonos, ataxy. D.'s cases of N which are shown only against the background of intercurrent diseases are described.
In blood at biochemical, a research find high concentration of a leucine (norm — 1,4 — 2,0 mg of %), an isoleucine (norm — 0,9 — 1,5 mg of %), valine (norm of 2,0 — 2,9 mg of %) at the normal and even reduced content of other amino acids; sometimes hypoglycemia and anemia. Along with moderate quantity of a leucine, isoleucine, valine and methionine find in urine also tyrosine, phenylalanine, glyutaminovy to - that, threonine, taurine, citrulline, asparagine, glutamine, asparaginic to - that; sometimes define protein. Presence at urine at large amounts of alpha ketonic acids — derivative amino acids with a branched chain is characteristic.
the Diagnosis is based on a wedge, a picture, a characteristic smell of urine, positive test with 2 — 4-dinite-rofenilgidrazinom on alpha ketonic acids and hromatografichesky researches of a range of amino acids of blood and urine. The differential diagnosis is carried out with an intracranial birth trauma (see. Fenilketonuriya ), gipermetioninemiya (see), gipervalinemiya (see). Unlike a birth trauma, nevrol, symptoms appear with 3 — the 4th day of life. At a gipermetioninemiya the progressing drowsiness, tendency to bleedings is noted, aminoaciduria (see) with the increased release of methionine and tyrosine.
Treatment consists in purpose of a special diet.
Forecast in the absence of a dietotherapy adverse: the zabolvaniye progresses.
Bibliography: Badalyan L. O., Tabolin V. A. and Veltishchev Yu. E. Hereditary diseases at children, M., 1971, bibliogr.; Makkyyusik V. A. Ancestral features of the person, the lane with English, page 347, M., 1976; Moves of l of l of G. and To N and p p And. Early diagnosis of a fenilketonuriya, homocystinuria and disease of «maple syrup of urine» in GDR by microbiological inhibitory test of Guthrie, Pediatrics, No. 12, page 27, 1974, bibliogr.; KoeppP.u.a. Maple syrup urine disease variant, Z. Kinderheilk., Bd 116, S. 177, 1974, Bibliogr.
V. P. Lebedev, M. F. Logachev.