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Last updated:
June 28, 2019
Years published: 1988, 1989, 1997, 1998, 2005, 2019
NORD gratefully acknowledges Laina Lusk, NORD Editorial Intern from the Emory University Genetic Counseling Training Program and Cecelia A. Bellcross, PhD, MS, CGC, Associate Professor, Director, Genetic Counseling Training Program, Emory University School of Medicine, for assistance in the preparation of this report.
Cerebrocostomandibular syndrome (CCMS) is a disorder that involves a small chin (micrognathia), an opening in the roof of the mouth (cleft palate), a narrow chest, missing ribs, gaps between ribs, and breathing and feeding difficulties. Other common features include scoliosis, developmental delay or intellectual disability, and hearing loss. Other medical problems can be seen as well. Breathing difficulties can lead to death in childhood, and most babies born with CCMS need surgery in the first year of life to help them breathe. These surgeries can include inserting a breathing tube directly into the throat (tracheostomy), surgeries to make the jaw or chest larger, surgery to insert a feeding tube into the stomach, and surgery to repair the hole in the roof of the mouth. CCMS is caused by changes in the SNRPB gene. A damaging change in one of a person’s two copies of the gene can cause the disorder. Most of the time, these changes are new to a child, and do not show up in family members. Rarely, a parent may have the change as well, and may show no symptoms. The diagnosis of CCMS is usually made in the first year of life based on the clinical features (such as a small jaw, rib gaps, narrow chest, and/or breathing difficulties). Imaging techniques like X-ray or MRI may be needed to take a better look at the ribs and spine. Genetic testing can confirm the diagnosis and help parents to better understand the risk for having another child with the disorder.
CCMS is an extremely rare inherited disorder. Its features mainly stem from problems in how the jaw and ribs are formed. People with CCMS have a small jaw with a small chin and mouth (micrognathia). This can cause the tongue to be in the wrong position (glossoptosis). In turn, the abnormal position of the tongue can cause a gap to form in the roof of the mouth (cleft palate) during development in the womb. This set of features (micrognathia, glossoptosis, and cleft palate) is often called Robin sequence. These features can cause feeding difficulties. Nearly all people with CCMS have a small jaw, and most have cleft palate.
Individuals with CCMS have large gaps between some of their ribs, especially in the back of the ribcage near the spine. They are typically missing some ribs as well. In one study, people with CCMS had between 7 and 11 ribs per side instead of the typical 12. All had a least one gap on each side. Some patients had gaps between nearly all their ribs. Some of these gaps healed over time. In addition, the ribs of people with CCMS do not connect to the spine in the way they should (abnormal costotransverse articulation). Most people with CCMS also have narrow rib cages. The narrow rib cage and jaw problems can make it difficult for people with CCMS to breathe and eat. These problems usually need treatment in the first year of life. Previously, only about 50% of babies born with CCMS lived until their first birthday. However, treatments have improved, and now about 80% of babies with CCMS live to be at least one-year-old. Many people with CCMS can live full, productive lives.
Scoliosis is another common feature in CCMS, though it tends to develop during childhood rather than appearing in infants. Scoliosis may affect about half (50%) of people with CCMS. About half of these patients, or 25% of all CCMS patients, have severe scoliosis. The rib gaps in CCMS cause the scoliosis, but the number of rib gaps cannot predict how severe the scoliosis will be.
About half (50%) of people with CCMS have developmental delays or intellectual disability. These delays can often be explained by a lack of oxygen at birth. The delays can be mild, moderate or severe. Severe delays may be related to more severe health problems overall. In some very severe cases of CCMS, babies die within the first year of life. Extra skin at the back of the neck (called redundant neck skin or neck webbing) may be a sign of this more severe form of CCMS.
Some other features of CCMS include hearing loss, clubfeet, small head, and low weight and height. They can also have problems with the stomach, heart, kidneys, and urine and genital pathways. Conductive hearing loss occurs in about two thirds (67%) of people with CCMS, where problems in how the ears are formed prevents normal hearing. Another type of hearing loss, called sensorineural hearing loss, has been found in at least one person with CCMS. This involves a problem in how noise signals are sent from the ears to the brain. Around one third (31%) of patients with CCMS have a problem where stomach acid travels back up into the throat (gastroesophageal reflux disease, shortened to GERD in the US and GORD in the UK). About one fourth (25%) are born with a hole in the heart. Problems with the urinary and genital pathways include testicles that remain inside the body (cryptorchidism) or a block in the anus (anal stenosis).
During pregnancy, some features of CCMS may be found by ultrasound. Around one fourth (19%) of people with CCMS in one study had a small jaw (micrognathia) on ultrasound. Some other ultrasound findings included slow growth (intrauterine growth restriction, or IUGR), extra amniotic fluid (polyhydramnios), and a thicker pocket of fluid at the back of the baby’s neck (thickened nuchal translucency). If this pocket of fluid becomes very large, it may be called a cystic hygroma. Extra fluid at the back of the neck while in the womb can lead to extra neck skin at birth, and may be linked to more severe problems in babies with CCMS.
The gene that is changed in patients with CCMS is the SNRPB gene. It is possible that there are other rarer causes of CCMS that have not been discovered yet, since some patients with CCMS do not seem to have a change in SNRPB.
We have two copies of nearly every gene: one copy from our mother and one copy from our father. A genetic disorder is called “dominant” if it is caused by a change or mutation in only one copy of a gene. The gene change could be passed on from the mother, passed on from the father, or a new change in the person with the disorder. If a person has a changed or mutated gene, they have a 50% chance of passing it on each time they have a child. The chance is the same for each child. It does not matter is the child is male or female.
In some individuals, the disorder is due to a new or spontaneous (de novo) genetic change that occurs in the egg or sperm cell. In these cases, the disorder is not inherited from the parents. This is the most common case for children born with CCMS, and is seen in about two thirds (67%) of CCMS patients. However, there have been a few cases where a child with CCMS inherited a genetic mutation from a parent. The parent may or may not show features of CCMS. It is unknown why some people do not show any symptoms of CCMS despite having a genetic change that causes the disorder. This is called incomplete penetrance. This seems to happen in around 20% of parents who have a child with CCMS.
Previous reports suggested that CCMS followed autosomal recessive inheritance, where both parents must be carriers for a child to have the disorder. However, since the gene for CCMS was discovered, no cases have been reported where both parents were carriers. The best current explanation for inheritance in CCMS is dominant inheritance with incomplete penetrance, as described above.
CCMS is a very rare disorder that is apparent at birth (congenital). The disorder appears to affect males and females in equal numbers. Over 80 patients have been reported in the medical literature.
In some patients, CCMS may be diagnosed before birth (prenatally) using advanced imaging techniques such as ultrasound. Fetal ultrasounds use reflected sound waves to make a picture of the developing fetus, and can show signs of CCMS (e.g., short, improperly formed ribs; small jaw; etc.).
In most patietns, CCMS is diagnosed and/or confirmed after birth (postnatally) based upon a thorough clinical evaluation, classic physical findings, and imaging tests. For example, x-ray studies may confirm or reveal the severity of jaw and rib problems, as well as other features of CCMS.
Treatment
The treatment of CCMS is based on the symptoms that a person with CCMS has. Treatment may require a group effort from a team of specialists. Pediatricians, surgeons, physicians who diagnose and treat abnormalities of the lungs (pulmonologists), specialists who assess and treat hearing problems (audiologists), speech pathologists, and other health care professionals may need to work together to plan a child’s treatment.
Specific therapies for the treatment of CCMS are meant to ease the burden of specific symptoms. Because infants with the disorder may be prone to breathing problems and infections, doctors may closely watch babies with CCMS, recommend preventive treatments, and aggressively treat infections with antibiotics. In cases of severe breathing problems in the first few months of life, a cut may be made into the windpipe (trachea) to create a temporary opening (tracheostomy) that will allow the baby to breathe more easily. About one third (1/3) will still need breathing support after this procedure. This can include continuous oxygen through a tube under the nose or a small portable breathing machine (continuous positive airway pressure, or CPAP).
In addition, special therapies may help babies with feeding problems to get enough food and nutrients. For example, babies born with a hole in the roof of the mouth (cleft palate) need special bottle nipples for feedings, and typically need surgery to repair the roof of the mouth. Most babies born with CCMS need to have a tube placed into their bodies to help with feeding. This can be through the baby’s nose (nasogastric tube, or NG tube) or directly into the baby’s stomach (gastrostomy tube, or G tube). Other surgeries may be considered , such as surgery to make the jaw or chest larger.
The vertical expandable prosthetic titanium rib (VEPTR) was approved by the FDA in 2004 as a treatment for thoracic insufficiency syndrome (TIS) in pediatric patients. TIS is a disorder where severe problems in how the chest, spine, and ribs are formed prevent normal breathing and lung development. The VEPTR is device helps straighten the spine and separate ribs so that the lungs can grow and fill with enough air to breathe. It is placed inside the body and its size can be adjusted as the patient grows. The titanium rib was developed at the University of Texas Health Science Center in San Antonio. It is made by Synthes Spine Co.
Hearing aids may be helpful for people with CCMS who have hearing loss. Early intervention services can help children with CCMS reach their potential. These include special education, speech therapy, and other medical, social, and/or job skills services.
Genetic counseling can be helpful for all people with CCMS and their families. Genetic counselors can explain CCMS and the chance that another child in the family will have it. They can also help families connect to resources and other people with CCMs.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.
For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:
Toll-free: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov
Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/
For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com
For information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/
(Please note that some of these organizations may provide information concerning certain conditions potentially associated with this disorder [e.g., cleft palate, respiratory abnormalities, hearing loss, etc.].)
JOURNAL ARTICLES
Tooley M, Lynch D, Bernier F, et al. Cerebro–costo– mandibular syndrome: Clinical, radiological, and genetic findings. Am J Med Genet Part A. 2016;170A:1115–1126.
Lehalle D, Wieczorek D, Zechi-Ceide RM, et al. A review of craniofacial disorders caused by spliceosomal defects. Clin Genet. 2015; 88:405–415.
Lynch DC, Revil T, Schwartzentruber J, et al. Disrupted auto-regulation of the spliceosomal gene SNRPB causes cerebro–costo–mandibular syndrome. Nature Communications. 2014;5:4483. doi:10.1038/ncomms5483.
Nagasawa H, Yamamoto Y, Kohno Y. Cerebro-costo-mandibular syndrome: Prognosis and proposal for classification. Congenital Anomalies. 2010; 50:171–174
INTERNET
McKusick VA, O’Neill MJF. Cerebrocostomandibular Syndrome (Entry Number 117650). Online Mendelian Inheritance in Man (OMIM). https://www.omim.org/entry/117650 Last update 04/14/2017. Accessed March 4, 2019.
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