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MBD5 gene

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

MBD5 gene

The MBD5 gene provides instructions for a protein that regulates gene expression and is essential for normal neurological development.

Normal Function

The MBD5 gene is one of a family of genes called the methyl-CpG-binding domain (MBD) genes. These genes provide instructions for making proteins that help regulate gene activity (expression) by modifying chromatin, the complex of DNA and protein that packages DNA into chromosomes. The MBD5 protein is likely involved in regulating gene expression and controlling the production of proteins that are involved in neurological functions such as learning, memory, and behavior. The MBD5 protein also seems to play a role in the growth and division (proliferation) and maturation (differentiation) of various types of cells.

Health Conditions Related to Genetic Changes

MBD5-associated neurodevelopmental disorder

Mutations in the MBD5 gene have been found to cause MBD5-associated neurodevelopmental disorder (MAND). MAND is a condition that affects neurological and physical development from birth. Affected individuals often have intellectual disability, developmental delay, impaired speech, sleep problems, distinctive facial features, and mild hand and foot abnormalities. Most people with MAND also have features similar to autism spectrum disorder, a developmental condition that affects communication and social interaction.

Some MBD5 gene mutations that cause MAND delete large segments of the MBD5 gene or result in the production of an altered protein with no function. These mutations affect one copy of the gene in each cell. As a result, there is less MBD5 protein available to regulate the expression of certain genes, leading to uncontrolled protein production. Proteins that play a role in neurological functions are particularly affected, which helps explain why MAND impacts brain development and behavior.

Additionally, an extra copy of the MBD5 gene or a loss of the whole gene in each cell can cause MAND. In these cases, MAND results from abnormal copying (duplication) or removal (deletion) of a small piece of the long (q) arm of chromosome 2 at position 2q23.1. The duplicated or deleted segments can vary in size but always include the MBD5 gene, and often additional genes. Researchers believe that MBD5 gene changes underlie most of the signs and symptoms of MAND.

Other Names for This Gene

  • methyl-CpG-binding domain protein 5
  • methyl-CpG-binding protein MBD5

Genomic Location

The MBD5 gene is found on chromosome 2.

Frequently Asked Questions

Diagnosis usually begins when a pediatrician or developmental specialist observes delays in speech, motor skills, or social interaction. Because symptoms can overlap with autism spectrum disorder or other genetic conditions, a geneticist will typically order a chromosomal microarray or whole exome sequencing test to identify specific mutations or deletions in the MBD5 gene. A clinical diagnosis is confirmed when the genetic test reveals a pathogenic variant in the MBD5 gene alongside characteristic physical features and developmental history.
Early signs often appear in infancy or early childhood and include significant delays in reaching developmental milestones, such as sitting, walking, or speaking. Many children exhibit hypotonia (low muscle tone), which can make movement difficult. Behavioral signs may include unusual sleep patterns, such as difficulty falling asleep or frequent waking, and social differences like limited eye contact or repetitive behaviors. Distinctive facial features, such as a broad forehead or downslanting eyes, may also be noted by healthcare providers during routine checkups.
In most cases, MAND is not inherited; it occurs as a de novo mutation, meaning the genetic change happens spontaneously in the egg or sperm cell or very early in embryonic development. This is why parents of a child with MAND typically do not have the condition themselves and have a low risk of having another child with the same disorder. However, in rare instances, a parent may carry a mild mutation that does not cause symptoms in them but is passed to the child, leading to the disorder.
There is no cure for MAND, so treatment focuses on managing symptoms and improving quality of life. Early intervention is critical and typically includes speech therapy to address communication delays, occupational therapy to help with fine motor skills and sensory processing, and physical therapy to improve strength and coordination. Behavioral interventions, such as applied behavior analysis, are often used to address autism-related challenges. Medications may be prescribed to manage specific issues like sleep disturbances, seizures, or attention deficits, but these do not treat the underlying genetic cause.
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.