Singleton-Merten Syndrome 1
Patient Information
Characteristics
Background and History
This is a rare inherited syndrome characterized by abnormalities in the heart, aorta, face, eyes, teeth, and bone. There is considerable clinical variation in the features.
Clinical Correlations
The bones lack normal mineralization (such as calcium) with cavitation (empty spaces). The forehead is broad and the hairline is high. The lower jaw appears to recede. The heart valves and the aorta are calcified in some individuals in childhood and there is often severe heart disease
which can be responsible for early death. The bone disease results in short stature as well as periodontal disease. The teeth may have shortened roots while both primary and permanent tooth eruption can be delayed. The hip socket is often shallow resulting in a high risk of hip displacement.
The skin is dry and scaly and resembles psoriasis. Glaucoma has been diagnosed in some individuals in early childhood or in puberty. The muscles have reduced tone and there may be generalized weakness. This can be exacerbated by febrile illnesses.
Genetics
Inheritance
This is an autosomal dominant condition resulting from a change (mutation) in a single copy of a specific gene. Parents with milder disease are able to pass the mutation directly to their children with a 50% probability in each case.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
Diagnosis and Prognosis
Orthopedists, dentists, ophthalmologists, cardiologists, dermatologists, and pediatricians are likely to be involved in the care and treatment of this condition. The periodontal disease requires constant surveillance and prophylactic care. Evaluation for glaucoma requires frequent pressure measurements by an ophthalmologist. Frequent cardiac examinations should be done especially since heart disease is often present and responsible for the death of young people, even before adulthood.
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