Investigation of albinism genes in congenital esotropia.
OBJECTIVE
Esotropia is a feature of albinism. Amongst esotropic patients there may be mild unrecognised albinos. Oculocutaneous albinism shares several clinical features with congenital esotropia. It is well known that mammals with oculocutaneous albinism have misrouted retinal ganglion cell axons, most likely caused by the absence of melanin or DOPA during development. We investigated the hypothesis that mutations in the albinism genes Tyrosinase, the P Gene, and TYRP1 may also be responsible for congenital esotropia via a similar mechanism.


METHODS
We screened these three genes in 21 families with congenital esotropia using single stranded conformational polymorphism analysis.


RESULTS
No rare sequence variants segregating with esoptopia were detected. A novel silent mutation of the TYRP1 gene was identified in one pedigree but is not likely to be causative. Several previously reported common polymorphisms were detected but do not segregate with disease in this population.


CONCLUSIONS
Rare mutations of these genes do not appear to be responsible for congenital esotropia. Although we found no evidence for segregation of common variants with disease, these require further investigation for a possible contribution to a complex threshold model. Several lines of evidence indicate a genetic componenet of congenital esotropia, however, this is the first investigation of candidate genes for this disorder.
Burdon
Kathryn P
KP
Menzies Centre for Population Health Research, University of Tasmania, Hobart, Australia.
Wilkinson
Robin M
RM
Barbour
Julie M
JM
Dickinson
Joanne L
JL
Stankovich
James M
JM
Mackey
David A
DA
Sale
Michele M
MM
D016115:Albinism, Oculocutaneous / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D004948:Esotropia / Q000151:congenital*; D006801:Humans; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D014442:Monophenol Monooxygenase / Q000235:genetics*; D009154:Mutation; D010088:Oxidoreductases; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational; D011506:Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA
D002352:Carrier Proteins; D017931:DNA Primers; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C489600:OCA2 protein, human; D011506:Proteins; D010088:Oxidoreductases; C489799:TYRP1 protein, human; C064056:tyrosinase-related protein-1; D014442:Monophenol Monooxygenase