Our 2018 Research Agenda

We are fundraising for three groundbreaking projects. Learn more »

Our goal: $200,000


What is M-CM?

M-CM stands for macrocephaly-capillary malformation. It is a rare genetic syndrome that causes irregular growth in parts of the body and the brain. Specific effects and severity vary from person to person, but common characteristics are brain overgrowth, hypotonia (low muscle tone), and developmental delays. Many patients also have vascular birthmarks and body asymmetry.

Genetic Cause

M-CM is caused by mutations in a gene called PIK3CA that increase the activity of the gene. In most cases, these mutations happen spontaneously after conception, so that the gene is changed in a percentage of the body's cells. There are currently no known cases of inheritance. M-CM is one of many conditions caused by changes in PIK3CA and is part of a group of conditions known as PIK3CA-related overgrowth spectrum or PROS.

Many Names

This condition was first defined in 1997 as M-CMTC for macrocephaly-cutis marmorata telangiectatica congenita. In 2007, M-CM for macrocephaly-capillary malformation was proposed to more accurately describe the vascular involvement. A newer name, MCAP for megalencephaly-capillary malformation was proposed in a 2012 paper that is now widely used in genetics literature. These names, along with other variations, all refer to the same condition.


Ride the RARE Carousel of Possible Dreams

The M-CM Network is participating in a collaborative fundraiser as part of Rare Disease Day 2018 with Global Genes and The Festival of Children Foundation. You can join our team or contribute to a team member here.

Our 2018 Wall Calendar

Our annual wall calendar featuring M-CM patients from all over the world is available for purchase from print-on-demand service Lulu.com, get yours.

Rare Disease Day at Helen DeVos Children's Hospital

This gathering and panel discussion in Grand Rapids, MI will be co-hosted by M-CM parent Shannon Bennett. Details & registration »

Clinical Trial Opportunity

A clinical trial, “A Phase 1/2 Study of ARQ 092 in Patients with Overgrowth Diseases and Vascular Anomalies with Genetic Alterations of the PI3K/AKT Pathway” is enrolling at Boston Children's Hospital. More information »


Our brochures have recently been updated. We can send you paper copies by request, or you can download a PDF. Families tell us that they appreciate sharing them with medical professionals, school personnel, friends, and family. Learn more »

Newly diagnosed?

Join our contact registry.

This lets us keep you informed of new discoveries and opportunities to participate in research and clinical trials. It also helps us to know how many M-CM patients there are, and where they are. Join now.

Connect with the community.

The online patient community is a rich source of support and information. Groups on Facebook include

Get involved.

Patients can advance research by contributing tissue samples and enrolling in research studies and clinical trials. Learn about ways to fundraise for the M-CM Network, or let us know how you would like to help.