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Reviewed December 2015
What is 3MC syndrome?
3MC syndrome is a disorder characterized by unusual facial features and problems affecting other tissues and organs of the body.
The distinctive facial features of people with 3MC syndrome include widely spaced eyes (hypertelorism), a narrowing of the eye opening (blepharophimosis), droopy eyelids (ptosis), highly arched eyebrows, and an opening in the upper lip (cleft lip) with an opening in the roof of the mouth (cleft palate). Common features affecting other body systems include developmental delay, intellectual disability, hearing loss, and slow growth after birth resulting in short stature. Other features of 3MC syndrome can include abnormal fusion of certain bones in the skull (craniosynostosis) or forearm (radioulnar synostosis); an outgrowth of the tailbone (caudal appendage); a soft out-pouching around the belly-button (an umbilical hernia); and abnormalities of the kidneys, bladder, or genitals.
3MC syndrome encompasses four disorders that were formerly considered to be separate: Mingarelli, Malpeuch, Michels, and Carnevale syndromes. Researchers now generally consider these disorders to be part of the same condition, which is called 3MC based on the initials of the older condition names.
How common is 3MC syndrome?
3MC syndrome is a rare disorder; its exact prevalence is unknown.
What genes are related to 3MC syndrome?
3MC syndrome is caused by mutations in the COLEC11 or MASP1 gene. These genes provide instructions for making proteins that are involved in a series of reactions called the lectin complement pathway. This pathway is thought to help direct the movement (migration) of cells during early development before birth to form the organs and systems of the body. It appears to be particularly important in directing the migration of neural crest cells, which give rise to various tissues including many tissues in the face and skull, the glands that produce hormones (endocrine glands), and portions of the nervous system.
The COLEC11 gene provides instructions for making a protein called CL-K1. Three different proteins, MASP-1, MASP-3, and MAp44 can be produced from the MASP1 gene, depending on how the gene's instructions are pieced together. The MASP1 gene mutations identified in people with 3MC syndrome affect the MASP-3 protein; some affect the MASP-1 protein in addition to MASP-3.COLEC11 and MASP1 gene mutations that cause 3MC syndrome impair or eliminate the function of the corresponding proteins, resulting in faulty control of cell migration in embryonic development and leading to the various abnormalities that occur in this disorder.
In some people with 3MC syndrome, no mutations in the COLEC11 or MASP1 gene have been identified. In these individuals, the cause of the disorder is unknown.
How do people inherit 3MC syndrome?
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Where can I find information about diagnosis or management of 3MC syndrome?
These resources address the diagnosis or management of 3MC syndrome and may include treatment providers.
- Genetic Testing Registry: Carnevale
- Genetic Testing Registry: Craniofacial-ulnar-renal
- Genetic Testing Registry: Malpuech facial clefting
- Genetic Testing Registry: Michels
You might also find information on the diagnosis or management of 3MC syndrome in Educational resources and Patient support.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about 3MC syndrome?
You may find the following resources about 3MC syndrome helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for 3MC syndrome?
- Carnevale-Krajewska-Fischetto syndrome
- Carnevale syndrome
- craniofacial-ulnar-renal syndrome
- craniosynostosis with lid anomalies
- Malpuech facial clefting syndrome
- Malpuech syndrome
- Michels syndrome
- Mingarelli syndrome
- oculopalatoskeletal syndrome
- oculo-skeletal-abdominal syndrome
- OSA syndrome
- ptosis of eyelids with diastasis recti and hip dysplasia
- ptosis-strabismus-rectus addominis diastasis
What if I still have specific questions about 3MC syndrome?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
- What does it mean if a disorder seems to run in my family?
- What are the different ways in which a genetic condition can be inherited?
- If a genetic disorder runs in my family, what are the chances that my children will have the condition?
- Why are some genetic conditions more common in particular ethnic groups?
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding 3MC syndrome?
autosomal ; autosomal recessive ; blepharophimosis ; caudal ; cell ; Cl- ; cleft palate ; craniofacial ;craniosynostosis ; developmental delay ; disability ; dysplasia ; embryonic ; gene ; genitals ; hernia ;hypertelorism ; inherited ; nervous system ; neural crest ; palate ; prevalence ; protein ; ptosis ;recessive ; renal ; short stature ; stature ; strabismus ; syndrome
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (7 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook