Суббота, Май 25, 2019

Diagnosis and treatment of disorders of amino acid metabolism in autism

КОММУНАЛЬНОЕ НЕКОММЕРЧЕСКОЕ ПРЕДПРИЯТИЕ ХАРЬКОВСКОЙ ОБЛАСТНОЙ РАДЫ «Межобластной специализированный медико-генетический центр редких (орфанных) заболевани»
Харьковский специализированный медико-генетический центр (ХСМГЦ) занимается исследованиями в генетике и эпигенетике, диагностикой и лечением аутизма, дефицита внимания, слуховой нейропатии, муковисцидоза, нарушений метаболизма, обмена аминокислот, а также других редких генетических (орфанных) заболеваний.
Харьков, Проспект Независимости, 13
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Diagnosis and treatment of disorders of amino acid metabolism in autism

When AUTISM and autistic features of behavior have the metabolic base – this, on the one hand, worsens course severity, on the other hand – gives the concrete direction of the treatment . Since a human began to intervene into actions of a natural selection, it has to change levels of its influence turning one stage of ontogenesis to another. Attempts of saving interruptive in early terms of a pregnancy with the help of medicines lead to pretended victory – the frequency of birth of children with the inborn and inherent pathology by our data increases 4 times. (E.Y. Grechanina, 2012) 

Obstetrical anamnesis in metabolic diseases - Spontaneous abortion or deadborn in the anamnesis should be considered as elimination of an unviable child. -Male gender of such fetus can say about X-linked form of metabolic diseases; -The presence of pathologic changes in a pregnant, such as continued toxicosis or an acute fatty dystrophy of the liver, can be the result of the disorder of fatty acid oxidation in a fetus.

When it is necessary to suspect metabolism disorder?

  • Lethargy
  • Refuse from food
  • weight loose
  • breath disturbance
  • hypothermia
  • hypotonia
  • unusual motions 
  • hepatomegaly
  • convulsions
  • polyorgan changes
  • coma

Preanalytical stage:

  • Somatic and genetic study
  • syndromologic, clinical and genealogical analysis
  • Preparation of a patient for the study
  • Sampling of the biochemical material
  • Preservation and transport of samples

Organic acids – low molecular compounds, which are products metabolism of amino acids, hydrogen, lipids, biogenic amines. Organic acidurias (acidemias) – a group of inherent diseases, which is characterized by the disorder of intermediate metabolism with the accumulation of carboxyl acids. Toxic compounds disturb intercellular metabolic pathways, including glucose catabolism (glycolysis), glucose synthesis (gluconeogenesis), metabolism of amino acids and pyrimidines and also fats .

Types of organic acids (ОА) 

  • ОА, caused by the deficiency of enzymes participating in transformation of amino acids (leucine, isoleucine, valine, lysine, tyrosine, aminobyturic acid).
  • ОА, caused by the disorder of bioenergy processes (Creb’s cycle), cellular breath, oxidative phosphorylation in mitochondria of cells.
  • ОА, caused by the disorder of transport or mitochondrial oxidation of fatty acids.

There are the following disorders of AA metabolism • Breakdown of protein lead to the formation of a great amount of nitrogen – a substance, which is highly toxic for CNS. Nitrogen is usually converted in urea and released with urine. • *Defects of enzymes of urea cycle and other disorders of detoxification of ammonia are manifested clinically in the form of encephalopathy and hyperammonemia *Study of metabolism should include analysis of amino acids of blood and urine in determination of orotic acid in urine.

Disorder of transport of amino acids Defects of intestine and/or renal transport of AA can be:

  • asymptomatic 
  • Manifested clinically as a deficiency of essential amino acids or as a result of the disorder of AA transport (e.g. tryptophan in Hartnup disease)
  • Followed by the increase of uric concentration of unsolved AA (e.g. cystine in cystinuria)

Clinical features of some aminoacidopathies

  • Combination of mental retardation (MR) with convulsions (non ketotic hyperglycinemia, PKU, disorder of metabolism of AA of urea cycle, hyperlysinemia); Combination of MR with pathology of vision (homocystinuria);
  • Combination of MR with skin affection (PKU, inherent xanturenuria, histidinemia);
  • Combination of the affection of the liver and CNS (argininemia);
  • Hearing disorder (hyperprolinemia).

Characteristic deficiency of amino acids in autism • According DAN theory: taurine is decreased and its intake is recommended in a high dose in chelation • In statistical study of Moreno-Fuenmayor et al., performed in 1996 year,it was proved that 50% of children had an increased level of taurine, that was explained by compensatory character. Statistical study of 330 analyses in KhSMGC has shown its increase in 56% cases (that corresponds to serious study data), and its decrease only in 1 case. In considering other amino acids, DAN-theory is plastic in explanation (the decrease of amino acids in plasma, not connected with a diet, DANtheory connects with two well-known effects of mercurous: inhibition of chorohydric acid development in ventricle, inhibition of various proteases and peptides, that creates problems for amino acid absorption, but self-confident in treatment: “tests can be not the best indicators, real test of therapy is more reliable”.  DAN-theory recommends to increase the amount of proteins (proteins in food).  Producers of BAA, more often using Bioshape and Protivity, also take part (isoleucine, methionine, valine, tryptophan, phenylalanine, lysine, valine), persuade the consumer in that there is no a single person, whom wasn’t prescribed periodical intake of amino acids.

Examination of children older than 10 years, performed in 1996, showed that the concentration of glutamate and aspartate were appeared to be enough high, and glutamine and asparagine – low, the half of children had the increase of taurine. There is a hypothesis that abnormality of glutamate levels can be caused by the presence high amounts of this amino acid in food, can have endogenic pattern (the result of disorder of metabolism of glutamate, receptor blockage and carrier function change).The increase of taurine concentrations, most probably, has compensatory pattern.

The conclusion was made: children with autism are born in families with disorder of the regulation of amino acid metabolism, tat indicates the biochemical basis of this disease.

In I.S. Boksha’s opinion, 2005, such changes of amino acids correspond to glutamate neuromediate system and disorder (or change of synthesis speed) of the structure of neuromediate system components (receptors and carriers), including glutamate and cholinergic, serotonergic, dopaminergic, and also neuromediator metabolism play the key role in autism development.

 

 

 

Y.B. Grechanina

2019-04-17 15:23:48