PRA (Progressive Retinal Atrophy) APR (Atrophie Progressive de la Rétine).

Czech Rep (Genomia) France: APR Atrophie Progressive de la Rétine
PRA-rcd2 (rod-cone dysplasia) is one of the forms of Progressive Retinal Atrophy (PRA) with very early onset of the disease. Some forms of PRA are common to several races. This specific form of PRA-rcd2 affects collies (long-haired and short-haired). If the dog is affected by rcd2 disease, abnormal development (dysplasia) of rods and cones (photoreceptors) occurs. The development of photoreceptors is stopped and is followed by their fast degeneration. Both types of photoreceptors degenerate, while the rod degeneration is much faster than the cone degeneration and therefore, the night blindness occurs as first. Dysplasia results in night blindness by 6-week-old puppies. In affected puppies, the rod and cone cells gradually lose their normal function in outer segments of the affected retina (Santos-Anderson et al. 1980); by 2 to 2.5 months, no photoreceptors at the outer part of the affected retina can be found. In connection with rcd2 disease, there has been found an insertion 22 bp of exon 4 of RD3-gene, localised on 7th chromosome, in dogs (Kukekova et al. 2009).

La maladie génétique prcd-PRA provoque la dégénérescence et la mort des cellules de la rétine, à l'arrière de l'oeil, même si ces cellules semblaient se développer normalement plus tôt dans la vie du chien. Les cellules "rod" travaillent à des niveaux de lumière basse et sont les premières à perdre leurs fonctions normales. Il en résulte une cécité nocturne. Ensuite les cellules "cone" perdent petit à petit leurs fonctions normales dans des situations de pleine lumière. La plupart des chiens affectés deviendront aveugles. Les deux yeux sont toujours affectés.
Gène impliqué: exon 4 of RD3-gene

Règles de nommage Collie online: Autres conventions de nommage
(+/+) Non carrier Normal N/N (Negative/Negative)
(+/-) Carrier Carrier P/N (Positive/Negative)
(-/-) Affected Affected P/P (Positive/Postive)

PRA (Progressive Retinal Atrophy) Chiens testés (Tested dogs) 275

  1. PRA (+/+): 263   (95.6%)
  2. PRA (+/-): 12   (4.4%)
  3. PRA (-/-): 0   (0%)
Collie PRA