Keutel Syndrome is a rare genetic disorder characterized by abnormalities in cartilage and bone development, alongside effects on the cardiovascular system. It presents with physical characteristics that become apparent early in life.
What is Keutel Syndrome?
Keutel Syndrome is an extremely rare inherited condition, first identified in the early 1970s. It is classified as an autosomal recessive genetic disorder. While precise prevalence is low, with around 40-50 cases reported globally, it is estimated to affect fewer than 1 in 1,000,000 people.
Recognizing the Signs
Individuals with Keutel Syndrome display skeletal abnormalities. A consistent feature is the abnormal calcification of cartilaginous tissues, particularly in areas like the ears, nose, larynx, and tracheobronchial tree. Affected individuals frequently present with brachytelephalangism, which involves the shortening and broadening of the distal phalanges, most commonly the first to fourth fingers and toes. Short stature is also a common finding associated with the syndrome.
Cardiovascular issues are a common aspect of Keutel Syndrome, with peripheral pulmonary artery stenosis being a common congenital heart defect. Some patients may also develop arterial calcification. Beyond skeletal and cardiovascular features, individuals can have distinctive facial characteristics, including midface hypoplasia, a depressed nasal bridge, and a receding chin. Hearing loss is also a reported symptom, and recurrent ear and sinus infections may occur.
Genetic Basis
Keutel Syndrome is caused by mutations within the MGP gene, which codes for the matrix Gla protein. This protein plays an important role in inhibiting calcification in cartilage and vascular tissues. Mutations in the MGP gene lead to a loss of function, leading to abnormal calcification.
For a child to be affected, they must inherit two copies of the mutated MGP gene, one from each parent. Parents who carry only one copy of the mutated gene typically do not show symptoms themselves but have a 25% chance of passing the condition on to each of their children with each pregnancy.
Diagnosis and Management
Diagnosing Keutel Syndrome begins with a thorough clinical examination, identifying characteristic physical features. Imaging studies are then used to confirm suspected abnormalities. X-rays can reveal diffuse cartilage calcification and brachytelephalangism, key indicators. Computed tomography (CT) scans can help visualize the extent of calcification in various cartilaginous structures.
Echocardiography is performed to assess the cardiovascular system to identify peripheral pulmonary artery stenosis or other heart defects. Genetic testing, involving DNA sequencing to detect mutations in the MGP gene, provides a definitive diagnosis. This genetic confirmation is important for both diagnosis and genetic counseling for families.
Management of Keutel Syndrome is primarily supportive and requires a multidisciplinary approach due to the wide range of affected systems. Surgical interventions may be necessary to correct heart defects like pulmonary stenosis. Orthopedic specialists manage skeletal issues, including short stature and other bone abnormalities. Audiological support, such as hearing aids, is provided for individuals experiencing hearing loss. Ongoing monitoring for potential complications, including hypertension and respiratory issues, is important for comprehensive care.