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DHODH gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

DHODH gene

The DHODH gene provides instructions for making an enzyme essential for producing pyrimidines, the building blocks of DNA and RNA.

Normal Function

The DHODH gene provides instructions for making an enzyme called dihydroorotate dehydrogenase. This enzyme is involved in producing pyrimidines, which are building blocks of DNA and its chemical cousin RNA. Dihydroorotate dehydrogenase is found in mitochondria, which are the energy-producing centers inside cells. Specifically, this enzyme converts dihydroorotate to a molecule called orotate. In subsequent steps, orotate is modified to produce pyrimidines.

Health Conditions Related to Genetic Changes

Miller syndrome

Several variants (also called mutations) in the DHODH gene have been found to cause Miller syndrome, a rare condition that mainly affects the development of the face, arms, and legs. Most of the variants that cause Miller syndrome change single protein building blocks (amino acids) in dihydroorotate dehydrogenase.

Miller syndrome appears to disrupt the development of the pharyngeal arches, which are paired structures that form on each side of the head and neck during embryonic development. These structures ultimately develop into the bones, nerves, and muscles of the head and neck. Though dihydroorotate dehydrogenase appears to be active in the pharyngeal arches during embryonic development, it is not clear exactly how DHODH gene variants lead to the specific facial features seen in people with Miller syndrome.

The bones of the arms and legs often develop abnormally in people with Miller syndrome. During embryonic development, each limb starts out as a small mound of tissue called a limb bud, which grows outward. Though dihydroorotate dehydrogenase appears to be active in the limb buds during early development, it is not clear exactly how variants in the DHODH gene cause the specific bone abnormalities seen in people with Miller syndrome.

Other Names for This Gene

  • DHOdehase
  • dihydroorotate dehydrogenase
  • dihydroorotate dehydrogenase, mitochondrial
  • POADS
  • URA1

Frequently Asked Questions

Newborns require urgent evaluation of their airway and breathing due to micrognathia and cleft anatomy, alongside specialized feeding assessments to prevent aspiration. Audiological testing is essential because structural ear malformations frequently cause conductive hearing loss, requiring early placement of hearing aids or bone-conduction devices. In addition, an ophthalmology consult is needed to protect the exposed corneas caused by lower lid ectropion, and orthopedists must evaluate limb deficiencies to optimize functional mobility.
Miller syndrome, also known as postaxial acrofacial dysostosis, primarily affects the craniofacial structures and the limbs. Hallmarks include severe lower eyelid droop (ectropion or coloboma), cleft lip and/or cleft palate, a small jaw (micrognathia), malformed or cup-shaped ears, and postaxial limb reductions. The postaxial defects typically involve the absence or underdevelopment of the fifth (and sometimes fourth) digits on the hands and feet, occasionally accompanied by forearm bone abnormalities like ulnar hypoplasia.
No. Unlike many other genetic syndromes involving severe craniofacial malformations, intellectual development in individuals with Miller syndrome is usually normal. Developmental milestones can sometimes appear delayed early on due to hearing impairment, speech difficulties related to cleft palate, or physical limitations from hand anomalies, but cognitive abilities are typically preserved.
Miller syndrome is inherited in an autosomal recessive pattern. An affected individual must inherit two mutated DHODH genes, one from each parent. Parents of an affected child are typically asymptomatic carriers who have a 25% chance with each subsequent pregnancy of having another affected child, a 50% chance of having an asymptomatic carrier child, and a 25% chance of having a child with two normal copies of the gene.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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