Basel-Vanagaite-Smirin-Yosef Syndrome
Patient Information
Characteristics
Background and History
This is a recently reported condition of severe congenital malformations of the brain with marked developmental delay and eye abnormalities.
Clinical Correlations
Infants can be ‘floppy’ at birth and some have seizures. Individuals do not achieve the usual developmental milestones such as talking and walking. There may be a cleft palate, a ‘tented’ upper lip and a blood vessel anomaly called nevus flammeus on the forehead. There may be holes in internal heart structures. The brain can be deformed as well. Cataracts are often present at birth and the corneas can be small. The eyelids often droop. There may be strabismus (abnormal alignment of the eyes). Vision has not been tested.
Genetics
Inheritance
Genotyping has identified a mutation which in double dose seems to cause this condition. Parents with a single mutation are clinically normal but two such parents who have children can expect that 1 in 4 (25%) will have this condition.
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 clinical signs can be minimal and subtle at birth but the lack of development soon becomes evident. Cataracts can be diagnosed early. The onset of seizures along with the presence of the nevus on the forehead and the lack of development could suggest this disorder soon after birth to neurologists, and pediatricians but the diagnosis should be confirmed by gene studies.
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