[Corneal anomalies in murine trisomy 16]. / Minoranomalien der Hornhaut bei der murinen Trisomie 16.

BACKGROUND: The prevalence of human Down's syndrome is about 1:700. Investigations using animal models are therefore of clinical relevance for understanding its etiopathogenesis. No corneal changes have been reported with transgenic murine trisomy 16. METHODS: A total of 20 fetal mice (n=40 eyes) with experimentally induced trisomy 16 were investigated from day 18 of pregnancy in order to determine whether visible developmental disorders of the cornea occur. All specimen were investigated microscopically in serial sections. RESULTS: In addition to disturbances in systemic development, the transgenic mouse fetuses showed high rates of malformation of the eyes. Developmental and differentiation disorders of the corneal epithelial cell layers and structural disturbances of the corneal parenchyma were found. Our findings are the first demonstration of developmental disorders of the cornea in mouse fetuses with trisomy 16. These minor anomalies of the cornea could well have resulted in keratoconus if the animals had survived. CONCLUSIONS: Our findings in transgenic mouse fetuses with trisomy 16 correspond to the clinical pattern of Down's syndrome in humans. Disturbed development of lids and lenses have a high prevalence, whereas corneal hypoplasia is found less often.

[Ocular anomalies in Alagille's syndrome]. / Anomalies oculaires dans le syndrome d'Alagille.

The authors examine a family, in which two brothers were affected by a severe expression of arteriohepatic dysplasia (ADH, Alagille syndrome), an autosomal dominant disorder associated with intrahepatic cholestasis, characteristic facial appearance, congenital embryotoxon. One of these two cases presented a keratoconus and both had retinal pigmentary degeneration with pigment clumping. The father showed a benign expression of ADH, including the characteristic facial appearance and posterior embryotoxon. Another brother presented only retinal pigmentary abnormalities and a bilateral arcus senilis-like corneal opacity, without any other clinical sign of ADH. The presence of posterior embryotoxon in all the cases of Alagille syndrome confirms that this sign is a hallmark of ADH, also in its benign expression.