dichroismia

Dichroismia is a rare genetic disorder characterized by a deficiency in the enzyme dihydroorotate dehydrogenase (DHODH). This enzyme plays a crucial role in the de novo synthesis of pyrimidines, which are essential building blocks for DNA and RNA. The deficiency in DHODH leads to an accumulation of dihydroorotate and a depletion of pyrimidines, disrupting cellular processes, particularly in rapidly dividing tissues like the brain and bone marrow.

The symptoms of dichroismia can vary in severity and typically manifest in infancy or early childhood. Common features include intellectual disability, developmental delay, microcephaly (a smaller than normal head circumference), and seizures. Hematological abnormalities, such as anemia and neutropenia, can also be present due to impaired DNA synthesis in bone marrow cells. Other possible symptoms may include distinctive facial features, limb abnormalities, and issues with vision or hearing.

The disorder is inherited in an autosomal recessive pattern, meaning an individual must inherit two copies of the mutated gene, one from each parent, to be affected. Diagnosis is typically made through biochemical testing that measures DHODH enzyme activity and genetic testing to identify mutations in the DHODH gene. There is currently no cure for dichroismia, and treatment focuses on managing symptoms, such as anti-epileptic medications for seizures and supportive care for developmental and hematological issues. Research into potential therapeutic strategies aimed at bypassing or supplementing the deficient enzyme is ongoing.