Heart and Brain Malformation Syndrome
Patient Information
Characteristics
Background and History
This is a rare hereditary syndrome with malformations in the heart and brain.
Clinical Correlations
Clinically useful signs are present at birth, consisting of small heads and sometimes small eyes. The ears are low-set, malformed, and posteriorly rotated. There is poor muscle control (hypotonia) of the trunk while the limb reflexes are hyperactive. The nasal bridge is depressed and wide giving the appearance of abnormally widely spaced eyes. The palate in the mouth is highly arched while the lower lip is full and sometimes split (cleft lip). The heart, its valves, and the aorta may also have developmental defects.
Physical growth and psychomotor development are slow. Brain imaging shows severe abnormal development of tissues in the skull. Seizures may occur. Vision is poor but the cause of this remains unknown.
Genetics
Inheritance
A change (mutation) in both members of a specific pair of genes is responsible for this severe and complex condition inherited in an autosomal recessive pattern. Parents who carry a single mutation are clinically normal but when both carry the mutation each of their children have a 25% risk of inheriting the two mutations and manifesting this disorder.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
The facial and skull features should suggest this condition at birth but it is rare and not widely known. Pediatricians, cardiologists, ophthalmologists, and neurologists may collaborate in the diagnosis and care of this disorder. The physical defects are sufficiently severe so that death may occur within a few years of life. No treatment is known.
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