cystinosis

August 12, 2017 17:51 | Genetic Diseases

The disease is inherited in an autosomal recessive manner.Nature gene mutation is not installed.Currently there are following forms of cystinosis .

1. Heavy baby form. phenotypically Children are born healthy, but in the first months of life, they appear polyuria (excretion of more than normal amounts of urine), dehydration (loss of large amounts of fluid), persistent or recurring fever.Then the growth slows down and there are signs of rickets.However, they are not amenable to treatment with vitamin D. It appears photophobia, eye retina areas lack pigment combined with point pigmented clusters.Early sign - uniformly distributed sites corneal opacities, blood cells, even without color crystals of cystine are found.Further characterized by a sharp lag during growth and development of the child and the rapid development of renal failure with acidosis (a shift of acid-base balance of the body to the acid side), edema, anemia.Children die with symptoms of uremia (urine appearance of components in the blood

), before reaching the age of 10.Diathesis - a predisposition to the development of nephropathy.

2 .The juvenile form of cystinosis shown later, the growth of children is slowed down, also found retinal damage the eyes, photophobia.cystine crystals found in blood cells, bone marrow, cornea and conjunctiva.Pathology of the kidney develops slowly in the age of 10-12 years.There is no occurrence of amino acids in the urine, Fanconi syndrome does not develop.Chronic renal failure is formed during adolescence.

3. known benign form of cystinosis (adult type), which is not clinically evident, although crystals of cystine can be found in the blood and the cells of the cornea.

Detailed specifications deserves neonatal form of cystinosis.Early biochemical feature is the appearance of glucose in the urine (from traces to a sufficiently large number).It is also a characteristic feature of this disease is the appearance in the urine of a significant amount of amino acids.Urinary excretion of cystine increased to the same extent, which increases the excretion of other amino acids.Cystine kidney stones are rare.Isolation phosphate excretion combined with malabsorption of inorganic phosphate in the gut.Almost always it marked the appearance of protein in the urine.Although metabolic acidosis (pH shift to the acid side) in the blood, urine reaction is alkaline.This displays significant amounts of ammonium ions.If the damage of the glomerular apparatus of the kidneys in the urine appear red blood cells.Detected reduction of phosphate and potassium in serum.The residual nitrogen and blood urea has not changed in the early stages.

concentration of cystine in cells exceeds the normal values ​​by 100 times.The plasma does not reach the maximum permissible threshold.The intracellular deposition of cystine with cystinosis occurs when a perfectly normal activity of enzymes engaged in its degradation and oxidation.Almost 80% of intracellular cystine is included in the special cell granules, so it is unavailable for the enzyme, cleaving it.In the cells of the parents of children suffering from this disease, cystine content of up to 6 times higher than normal.It was significantly increased in the cells of the amniotic fluid during pregnancy homozygous fruit that can be used as a diagnosis of this pathology before birth.

treatment. proposed to use drugs penicillamine (dimetiltsisteina, cysteamine).Used kidney transplantation, with cystinosis expressed in the transplanted kidney does not develop.Proposed bestsistinovaya diet, as well as a protein substitute in the diet of amino acids mixture (without cystine).The effectiveness of the treatment of "synthetic diet" could not prove.