Meyahealth
HomeGeneticsConditionEnlarged parietal foramina
Back to Condition
Enlarged parietal foramina
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Enlarged parietal foramina

Enlarged parietal foramina is an inherited condition characterized by symmetrical, circular openings in the skull's parietal bones that remain open throughout life. While often harmless, this condition can increase the risk of brain damage or skull fractures from trauma.

Overview

Enlarged parietal foramina is an inherited condition of impaired skull development. It is characterized by enlarged openings (foramina) in the parietal bones, which are the two bones that form the top and sides of the skull. This condition is due to incomplete bone formation (ossification) within the parietal bones. The openings are symmetrical and circular in shape, ranging in size from a few millimeters to several centimeters wide.

Parietal foramina are a normal feature of fetal development, but typically they close before the baby is born, usually by the fifth month of pregnancy. However, in people with this condition, the parietal foramina remain open throughout life.

Symptoms & Clinical Features

The enlarged parietal foramina are soft to the touch due to the lack of bone at those areas of the skull. People with enlarged parietal foramina usually do not have any related health problems; however, scalp defects, seizures, and structural brain abnormalities have been noted in a small percentage of affected people.

Pressure applied to the openings can lead to severe headaches, and individuals with this condition have an increased risk of brain damage or skull fractures if any trauma is experienced in the area of the openings.

There are two forms of enlarged parietal foramina, called type 1 and type 2, which differ in their genetic cause.

Frequency

The prevalence of enlarged parietal foramina is estimated to be 1 in 15,000 to 50,000 individuals.

Causes

Mutations in the ALX4 gene account for 60 percent of cases of enlarged parietal foramina, and mutations in the MSX2 gene account for 40 percent of cases. These genes provide instructions for producing proteins called transcription factors, which are required for proper development throughout the body. Transcription factors attach (bind) to specific regions of DNA and help control the activity of particular genes. The ALX4 and MSX2 transcription factor proteins are involved in regulating genes that are needed in various cell processes in early development.

<

Frequently Asked Questions

Currently, there is no standard surgical technique to close enlarged parietal foramina, and most cases are managed conservatively. In very large or symptomatic openings, a neurosurgeon may consider a small bone graft or a protective overlay, but this is rare. The primary strategy is to monitor the size, educate patients on avoiding head trauma, and treat any resulting fractures promptly.
Because the condition is inherited in an autosomal dominant pattern, first‑degree relatives have a 50 % chance of carrying the same genetic variant. Genetic counseling and targeted DNA testing can confirm whether a family member carries the mutation, which helps guide surveillance and preventive measures. However, testing is optional and should be discussed with a genetics professional.===
Yes. Because the bone over the openings is thinner, even mild trauma—such as a fall, a bicycle crash, or a minor bump—can cause a skull fracture or, in rare cases, direct pressure on the brain. Children and adults with the condition should wear protective headgear during contact sports and be cautious around activities that carry a risk of head impact.
Parents should notice a soft, doughy area on the top of the child's skull that feels like a small bump or indentation. If the spot is painless but noticeably larger than the surrounding bone, or if the child reports headaches that worsen when pressure is applied to the area, a pediatrician or neurologist should examine the skull with a gentle palpation and possibly order a skull X‑ray or CT scan to confirm the presence and size of the foramina.
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.

Meyahealth

Ⓒ 2026. All rights reserved by MEYA

About UsTerms & PolicyFAQ