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PHF21A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PHF21A gene

The PHF21A gene provides instructions for a protein that regulates gene activity, playing a critical role in brain and facial development.

Normal Function

The PHF21A gene provides instructions for making a protein that helps regulate gene activity. The PHF21A protein interacts with proteins that modify histones—structural proteins that package DNA into chromosomes. By recognizing certain histone patterns, PHF21A helps regulate whether specific genes are turned on (active) or off (inactive). This protein is particularly important for the development of the brain and face.

Health Conditions Related to Genetic Changes

Potocki-Shaffer syndrome

Potocki-Shaffer syndrome is caused by a deletion of genetic material from chromosome 11, which includes the PHF21A gene. The loss of this gene is thought to play a major role in the intellectual disabilities and distinctive facial features associated with the syndrome. Other features caused by the loss of additional genes in this region include:

  • Enlarged parietal foramina (enlarged openings in the skull bones)
  • Osteochondromas (multiple noncancerous bone tumors)

PHF21A neurodevelopmental disorder

Pathogenic variants in the PHF21A gene cause PHF21A neurodevelopmental disorder, sometimes known as intellectual developmental disorder with behavioral abnormalities and craniofacial dysmorphism with or without seizures (IDDBCS). These variants disrupt the normal function of the PHF21A protein, impairing the activity of genes involved in brain and facial development. Common signs and symptoms include:

  • Faster than normal growth after birth
  • Macrocephaly (unusually large head size)
  • Intellectual disabilities
  • Behavioral problems
  • Low muscle tone
  • Seizures

Other Names for This Gene

  • BHC80
  • BM-006
  • KIAA1696

Frequently Asked Questions

Children with PHF21A variants often reach speech and motor milestones later than peers. Typical delays include delayed sitting, standing, and walking, and speech may begin after 2 years of age. Cognitive testing usually shows moderate to severe intellectual disability, and behavioral assessments often reveal hyperactivity, anxiety, or autism‑like features. Early intervention programs can help maximize functional outcomes.
Behavioral issues such as aggression, hyperactivity, or seizures benefit from a multidisciplinary approach. Structured behavioral therapy, applied behavior analysis, and social skills groups can reduce disruptive behaviors. If seizures are present, antiepileptic drugs tailored to the seizure type are essential. Pharmacologic treatment for attention or mood disorders (e.g., stimulants, selective serotonin reuptake inhibitors) may also be considered under specialist guidance.
Diagnosis is made by chromosomal microarray or whole‑genome sequencing that detects a deletion on chromosome 11q13.4‑q13.5, which includes PHF21A. The loss of PHF21A disrupts histone‑binding regulation, leading to the characteristic facial features, macrocephaly, and developmental delays seen in the syndrome. Genetic counseling confirms the deletion and explains recurrence risk.
If the mutation is a de‑novo point mutation, the recurrence risk for future children is low (≈1 %). However, if the mutation is inherited from a parent, the risk is 50 % for each pregnancy. For deletions involving PHF21A, parental testing is recommended to determine whether the deletion is inherited or new.
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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