Pathologic features of the eye in trisomy 9.

A clinical and pathologic study of a neonate with mosaic trisomy 9 revealed findings similar to those in other cases with this chromosomal anomaly. Except for deeply-set eyes and small palpebral fissures with slight telecanthus, our ocular findings have not previously been described in mosaic trisomy 9. The most striking ocular pathologic alterations involved the anterior segment and included a keratolenticular adhesion and marked iris hypoplasia. There were similarities to Peters' anomaly as well as to ocular lesions associated with aplasia of th optic nerve and Lowe's and Potter's syndrome. The ocular and extraocular anomalies in our patient appear to have resulted from a mesodermal dysgenesis operational between one and five and a half months of gestation.