Finnish heritage disease
A Finnish heritage disease is any genetic disease or disorder that is significantly more common in people whose ancestors were ethnic Finns, natives of Finland and Northern Sweden and Northwest Russia. There are 36 rare diseases regarded as Finnish heritage diseases. The diseases are not restricted to Finns; they are genetic diseases with far wider distribution in the world, but due to founder effects and genetic isolation they are more common in Finns.
Within Finland these diseases are more common in the east and north, consistent with their higher association with ethnic Finns than with ethnic Swedes. The Finnish disease heritage does not extend to other ethnic groups in the region, the Sámi and Karelians other than Finnish Karelians. It is attributed to a population bottleneck among ancestors of modern Finns, estimated to have occurred about 4000 years ago, presumably when populations practicing agriculture and animal husbandry arrived in Finland.
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. Most of the gene defects are autosomal recessives, so that if both the mother and father carry the same defect, the chance that their child will have the associated disease is 1 in 4. The molecular genetics of many of these diseases have been determined, enabling genetic testing, prenatal testing, and counseling. This has raised questions of bioethics and eugenics.
Finnish heritage disease types
There are 36 identified Finnish heritage diseases:- Amyloidosis, Finnish type
- Lethal arthrogryposis with anterior horn cell disease
- Aspartylglucosaminuria
- Autoimmune polyendocrinopathy syndrome, type I, with or without reversible metaphyseal dysplasia
- Cartilage–hair hypoplasia
- Ceroid lipofuscinosis, neuronal, 1
- Ceroid lipofuscinosis, neuronal, 3
- Ceroid lipofuscinosis, neuronal, 5
- Ceroid lipofuscinosis, neuronal, 8, Northern epilepsy variant
- Choroideremia
- Cohen syndrome
- Cornea plana 2
- Diarrhea 1, secretory chloride, congenital
- Diastrophic dysplasia
- Epilepsy, progressive myoclonic 1A
- Glycine encephalopathy
- GRACILE syndrome
- Gyrate atrophy of choroid and retina
- Hydrolethalus syndrome 1
- Infantile-onset spinocerebellar ataxia
- Lactase deficiency, congenital
- Lethal congenital contracture syndrome 1
- Lysinuric protein intolerance
- Meckel syndrome
- Megaloblastic anemia-1, Finnish and Norwegian type
- Mulibrey nanism
- Muscular dystrophy-dystroglycanopathy, type A, 3
- Nephrotic syndrome, type 1
- Ovarian dysgenesis 1
- Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy
- Progressive encephalopathy with Edema, Hypsarrhythmia and Optic atrophy
- RAPADILINO syndrome
- Retinoschisis 1, X-linked, juvenile
- Sialuria, Finnish type
- Tibial muscular dystrophy, tardive
- Usher syndrome, type 3A
Four genetically distinct subtypes of neuronal ceroid lipofuscinosis are found in the Finnish heritage: CLN1, CLN3, CLN5, and CLN8. Names for conditions associated with these subtypes include infantile neuronal ceroid lipofuscinosis, Jansky–Bielschowsky disease and northern epilepsy syndrome. As of 2001, CLN5 and CLN8 had been reported almost exclusively in Finland.
Meckel syndrome type 1, a lethal condition, is known in 48 Finnish families.
Other genetic diseases
The European Organization for Rare Diseases estimates that there are between 5,000 and 7,000 distinct rare diseases, affecting between 6% and 8% of the population of the European Union. The majority of genetic diseases reported in Finland are not part of the Finnish disease heritage and their prevalence is not higher in Finland than worldwide.Some genetic diseases are disproportionately rare in Finns. These include cystic fibrosis and phenylketonuria. In Finland, about 1 in 80 persons are carriers of a cystic fibrosis mutation, compared with an average of 1 in 25 elsewhere in Europe.