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

PIGN gene

The PIGN gene provides instructions for an enzyme involved in assembling GPI anchors, which are necessary for attaching proteins to the cell surface.

Normal Function

The PIGN gene provides instructions for making an enzyme called GPI ethanolamine phosphate transferase 1. This enzyme takes part in a series of steps that produce a molecule called a glycophosphatidylinositol (GPI) anchor. A GPI anchor attaches to many different proteins inside the cell, which are known as GPI-anchored proteins. After a GPI anchor binds to a protein, the GPI anchor attaches itself to the outer surface of the cell membrane, ensuring that the GPI-anchored protein is available when it is needed.

GPI-anchored proteins have a variety of roles, which include helping cells attach to one another (cell adhesion), relaying signals into the cells (cell signaling), and protecting cells from foreign invaders (cellular immunity).

Health Conditions Related to Genetic Changes

Fryns syndrome

Variants (also called mutations) in the PIGN gene have been found to cause Fryns syndrome in some people. This condition affects the development of many parts of the body. Most people with Fryns syndrome have a defect in the muscle that separates the abdomen from the chest cavity (the diaphragm), most commonly a congenital diaphragmatic hernia. Additional signs and symptoms can include distinctive facial features and abnormalities of the fingers and toes.

Other disorders

Variants in the PIGN gene can also cause a condition called multiple congenital anomalies-hypotonia-seizures syndrome 1 (MCAHS1). Many of the signs and symptoms seen in people with MCAHS1 overlap with those seen in people with Fryns syndrome, though people with MCAHS1 typically do not have a congenital diaphragmatic hernia. Some people with PIGN gene variants have neurologic signs and symptoms—such as weak muscle tone (hypotonia), developmental delays, intellectual disabilities, movement disorders, and seizures—without having all of the features of these specific disorders.

Other Names for This Gene

  • MCD4
  • Phosphatidylinositol glycan anchor biosynthesis class N protein
  • PIG-N

Frequently Asked Questions

PIGN gene variant is diagnosed through genetic testing, usually performed on a blood sample, which can identify specific mutations. If there is a family history of Fryns syndrome or MCAHS1, or if ultrasound findings during pregnancy suggest these conditions, prenatal genetic testing (e.g., amniocentesis or chorionic villus sampling) may be offered to determine if the fetus has a PIGN variant. Genetic counseling is crucial to interpret results and discuss reproductive options.
PIGN-related disorders, such as Fryns syndrome and MCAHS1, are typically inherited in an autosomal recessive pattern. This means that a child must inherit a PIGN gene variant from both parents to develop the condition. If one child is affected, both parents are usually carriers, and there is a 25% chance for each subsequent pregnancy to result in an affected child. Genetic counseling can help families understand these risks and explore options like prenatal diagnosis.
While both Fryns syndrome and Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome 1 (MCAHS1) are caused by PIGN gene variants and share features like developmental delay, distinctive facial features, and skeletal abnormalities, a key distinguishing factor is the presence of a congenital diaphragmatic hernia. This severe defect, where abdominal organs protrude into the chest, is a hallmark of Fryns syndrome but is typically absent in MCAHS1. MCAHS1 often presents with more pronounced hypotonia (low muscle tone) and seizures.
Children with PIGN-related disorders require comprehensive, multidisciplinary care. This often includes neonatology, pediatric surgery (especially for diaphragmatic hernia in Fryns syndrome), neurology for seizure management, physical and occupational therapy for developmental delays, speech therapy, and nutritional support. Regular monitoring for potential complications and ongoing supportive care are essential to optimize quality of life.
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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