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Possible complications

CMTC has many faces

CMTC is usually a fairly mild condition. However, a number of people with the disorder have been reported to have associated abnormalities.

The percentage of people with CMTC with such associated abnormalities varies quite a bit in the literature. There are many associated defects mentioned in CMTC. However, many abnormalities are not at all certain that there is a link between CMTC and the relevant associated abnormality.

Associated abnormalities

A number of people with CMTC may also experience other skin symptoms than the marbling of the skin. Sometimes sores can occur or the skin can become ‘thin’ locally. This is called ‘atrophy’. Sometimes another occurring abnormality is asymmetry of the limbs. Limbs can be thinner (hypotrophy) but sometimes also thicker (hypertrophy). See also our ‘photo gallery’ where, among other things, asymmetry of limbs is clearly visible. Other additional abnormalities may be: pink or dark red, irregularly shaped patches on the skin (naevus flammeus); loss of muscle tissue on one side of the body (hemiatrophy); increased fluid pressure in the eye (glaucoma). Many abnormalities represent forms of Klippel-Trenaunay syndrome or related conditions, in particular Cowden’s disease. The most common deviation from true CMTC is soft tissue (subcutaneous fat and muscle) hypoplasia (enlargement of tissue / organ as a result of abnormally high cell division).


The condition that was previously known as congenital macrocephaly-cutis marmoratatelangiectatica (M-CMTC) is a clearly different congenital disease than CMTC and is now called macrocephaly capillary malformations (M-CM / MCAP).

CMTC members

Looking at our members, we see a large variation in complications. Some have ‘only’ a visibly marbled skin while others have serious complications. In general we see asymmetry of limbs when these CMTC have ‘spots’. Currently, as far as we know, five children have died with very serious complications.

When CMTC ‘spots’ are found on the head, and especially in the face, it is advisable to contact an ophthalmologist who examines the patient for glaucoma (increased eye pressure). A visit to a pediatric neurologist is also recommended in such cases. Our experience is that very few doctors (worldwide) know and recognize CMTC.