Agenesis of cruciate ligaments and menisci causing severe knee dysplasia in TAR syndrome.

EDITOR—The syndrome of thrombocytopenia and absent radius (TAR syndrome) is an autosomal recessive condition characterised by congenital hypomegakaryocytic thrombocytopenia and bilateral radial aplasia with the presence of thumbs. 2 Associated abnormalities include other skeletal defects, cardiac malformations, and gastrointestinal disorders. Lower limb abnormalities, such as coxa valga, ankylosis of the knee, tibial torsion, and hip dislocation have been reported, 4 5 but severe knee dysplasia has rarely been described. We report a case of TAR syndrome presenting with phocomelia of the upper limbs and marked knee dysplasia owing to complete agenesis of the cruciate ligaments and severe hypoplasia of the menisci.