Did all three identical triplets have tonsillar ectopia?

Details

This case report describes monozygotic triplets, each with a different degree of tonsillar ectopia. Patient X presented with a Chiari I malformation and associated syringomyelia. Examination showed 4 mm of tonsillar ectopia in patient Y and 2.5 mm in patient Z.

The authors report that no such case had previously been reported in the literature. Their discussion defines current magnetic resonance criteria for diagnosing hindbrain malformations and considers whether these disorders form a spectrum or are separate disease entities, with particular emphasis on genetic predisposition. Because all three triplets were affected, a 100% concordance in this case, the authors suggest that a common hereditary factor is highly likely to contribute to the origin of these malformations.