Diagnosis and treatment of orphan disease — homocystinuria and megaloblastic anemia, type cblG

The term «homocystinuria» combines a number of genetically determined nosological forms caused by defects of the metabolism of sulfur-containing amino acids (methionine, homocysteine), cobalamin and folate. The group of these diseases includes «classical» homocystinuria caused by insufficiency of cystathionine beta-synthase and forms associated with defects in methionine remethylation processes. More information is given about one of these forms — homocystinuria and megaloblastic anemia, type cblG, caused by MTR gene mutations. The results of observation of a child with this disease are presented. The clinical status includes: intellectual disability, autistic behavioral traits, stereotypes, nystagmus, visual impairment, macrocytic anemia, epilepsy in remission. Effective treatment requires the use of medications not registered in the Russian Federation — betaine and hydroxocobalamin.