Carpenter Syndrome

What is Carpenter syndrome?

Carpenter syndrome is characterized by developmental issues, the premature fusion of bones in the skull, and abnormal fingers and toes. This condition is extremely rare, with only about 70 cases being described in medical literature.

What are the symptoms of Carpenter syndrome?

Because of the abnormalities of the skull, affected individuals’ heads appear pointed. They may also have an asymmetrical face and specific facial features, such as a flat nasal bridge, downward pointing eyes, low-set and abnormally shaped ears, abnormal eye shape, underdeveloped jaw, and dental abnormalities. The premature fusion may also result in vision problems and intracranial pressure.

In terms of fingers and toes, affected individuals may have two or more fingers/toes in which the skin is fused, extra fingers or toes, or unusually short fingers or toes. Intellectual disability is another common symptom, although it is not present in all cases. In a few cases, the organs are in reversed positions, such as the heart. This can impact blood flow.

Other symptoms include obesity, heart defects, hearing loss, skeletal abnormalities, genital abnormalities in males, and umbilical hernias.

What causes Carpenter syndrome?

A mutated RAB23 or MEGF8 gene causes Carpenter syndrome. The former plays a role in vesicle trafficking, the process in which proteins and other molecules are moved around within the cell. When this gene is mutated the process is altered, and in this case it leads to issues with a developmental pathway. This pathway plays a role in the normal shaping of the body. The latter is not yet understood, but medical professionals suspect that it is necessary for cell adhesion and normal body patterning. Both genes are inherited in an autosomal recessive pattern.

How is Carpenter syndrome diagnosed?

At times, this condition is diagnosed before birth. An ultrasound or fetoscopy can point a doctor towards a Carpenter syndrome diagnosis, which can be confirmed with prenatal molecular testing.

In most cases, diagnosis comes shortly after birth, as doctors notice the characteristic symptoms. They will perform a clinical evaluation, followed by specialized tests like CT scans, MRIs, and other diagnostic tests. Genetic testing can confirm. A cardiac evaluation is typically conducted as well, as heart defects are a common symptom.

What are the treatments for Carpenter syndrome?

Treatment for Carpenter syndrome is symptomatic and often requires a team of specialists. Surgery can be used to correct skeletal abnormalities, malformations of the fingers and toes, or cardiac issues.