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Miller-Dieker syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Miller-Dieker syndrome

Miller-Dieker syndrome is a rare genetic condition characterized by lissencephaly, a brain development pattern resulting in an abnormally smooth brain surface, leading to severe developmental and physical challenges.

Overview

Miller-Dieker syndrome is a condition characterized by a pattern of abnormal brain development called lissencephaly. Normally, the surface of the brain has folds and grooves. Lissencephaly causes the surface of the brain to be abnormally smooth, with fewer folds and grooves. In people with Miller-Dieker syndrome, lissencephaly is typically associated with severe intellectual disabilities, developmental delays, weak muscle tone (hypotonia), and seizures. Seizures usually begin in the first few months of life.

People with Miller-Dieker syndrome often have distinctive facial features, including:

  • A prominent forehead
  • A sunken appearance in the middle of the face
  • A small, upturned nose
  • Low-set and abnormally shaped ears
  • A small jaw

Some individuals with this condition also grow more slowly than their peers. Less often, affected individuals have heart problems, kidney abnormalities, or an opening in the wall of the abdomen that allows the abdominal organs to protrude through the navel. Because of these severe health issues, most individuals with Miller-Dieker syndrome do not survive beyond early childhood.

Frequency

Miller-Dieker syndrome appears to be a rare disorder, although its exact prevalence is unknown.

Causes

In the majority of cases, Miller-Dieker syndrome is caused by a deletion near the end of the short (p) arm of chromosome 17. This area of chromosome 17 is called the MDS critical region. Though the size of the deleted segment varies among affected individuals, it typically includes the PAFAH1B1 and YWHAE genes.

  • The loss of the PAFAH1B1 gene is responsible for the lissencephaly seen in people with this condition.
  • The loss of the YWHAE gene is thought to increase the severity of lissencephaly.
  • The loss of additional genes in the MDS critical region likely contributes to the other features of the syndrome.

In approximately 10 percent of people with the signs and symptoms of Miller-Dieker syndrome, the cause of the condition is unknown.

Inheritance

In most cases, Miller-Dieker syndrome is not inherited. The chromosome 17 deletion is usually a random event that occurs during the formation of reproductive cells (eggs or sperm) or during early fetal development. Affected people typically have no history of the disorder in their family.

Some people with Miller-Dieker syndrome inherit the condition from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which no genetic material is gained or lost. While balanced translocations usually do not cause health problems, they can become unbalanced when passed to the next generation, resulting in the loss of genetic material from the short arm of chromosome 17.

Frequently Asked Questions

Seizure control often requires a combination of antiepileptic drugs (AEDs) tailored to the infant’s EEG pattern. Common first‑line agents include phenobarbital or levetiracetam; if seizures persist, a second AED such as topiramate or clobazam may be added. Because the brain structure is abnormal, seizures can be refractory, so a pediatric neurologist may consider ketogenic diet therapy or vagus‑nerve stimulation in older children, though evidence is limited. Prompt treatment of each seizure episode is crucial to minimize additional neurologic injury.;How can families address feeding difficulties and ensure adequate growth in a child with Miller‑Dieker?::Most infants have poor suck‑swallow coordination and may require a feeding tube (gastrostomy or nasogastric) to meet caloric needs. A multidisciplinary team—pediatric gastroenterologist, speech‑language pathologist, and dietitian—can assess oral‑motor skills and recommend thickened feeds, paced bottle techniques, or specialized nipples. Regular monitoring of weight, length, and head circumference guides adjustments in caloric density and feeding schedule.;If an infant has an abdominal wall defect (omphalocele), what surgical options are available and when should they be performed?::Surgical repair is typically done within the first few days to weeks of life, depending on the size of the omphalocele and the infant’s overall stability. Small defects can often be closed primarily under general anesthesia. Larger defects may require staged closure using a silo or tissue expanders before final repair. The surgical team will coordinate with neonatology to manage respiratory and cardiac status before operating.;What is the expected life expectancy for children with Miller‑Dieker syndrome, and how can palliative care improve quality of life?::Life expectancy is generally limited, with many children not surviving beyond early childhood due to severe neurologic impairment, seizures, and respiratory complications. Palliative care focuses on symptom management (seizure control, comfort feeding, pain relief), psychosocial support for families, and advance‑care planning. Early involvement of a pediatric palliative‑care team can help coordinate home hospice services, provide respite care, and ensure that the child’s comfort and family’s goals are prioritized.;
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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