[3] In Finland about one in five persons carries a gene defect associated with at least one Finnish heritage disease, and about one in 500 children born is affected.
[5] There are 36 identified Finnish heritage diseases:[6][7] Out of these, three are rare causes of dwarfism: cartilage–hair hypoplasia, diastrophic dysplasia and Mulibrey nanism.
[8] Names for conditions associated with these subtypes include infantile neuronal ceroid lipofuscinosis, Jansky–Bielschowsky disease and northern epilepsy syndrome.
[12] Based on molecular data, a population bottleneck among ancestors of modern Finns is estimated to have occurred about 4000 years ago.
[3] This bottleneck resulted in exceptionally low diversity in the Y chromosome, estimated to reflect the survival of just two ancestral male lineages.