Congenital cornea plana in Finland

Two different hereditary forms of congenital cornea plana are described: an autosomal dominant form with relatively mild symptoms, and an autosomal recessive form (CPCR) with more severe symptoms, such as decreased visual acuity, extreme hyperopia (total refraction usually 10 D or more), hazy limbus corneae, more or less pronounced opacities in the corneal parenchyma, and marked arcus senilis, often detectable at an early age. As far as can be judged from the number of cases hitherto published, cornea plana is a rare disease. In Finland, 49 caw of the recessive and seven of the dominant form of cornea plana congenita have been discovered to date, which is about twice the number of cases of recessively inherited cornea plana reported elsewhere in the world. In Finnish Lapland, the gene frequency of cornea plana congenita recessiva is estimated to be 1.3 % (about 16 patients per 100,000 inhabitants), or about four times as high as in Finland as a whole. Around the lower reaches of the River Kemijoki there is a relatively high prevalence of the recessive form of the disease. The Kemijoki pedigree includes 25 patients related to each other through their ancestors.