A new locus for autosomal recessive nuclear cataract mapped to chromosome 19q13 in a Pakistani family.
OBJECTIVE
To identify the disease locus of autosomal recessive congenital nuclear cataracts in a consanguineous Pakistani family.


METHODS
A large Pakistani family with multiple individuals affected by autosomal recessive congenital cataracts was ascertained. Patients were examined, blood samples were collected, and DNA was isolated. A genome-wide scan was performed using 382 polymorphic microsatellite markers on genomic DNA from affected and unaffected family members. Two-point lod scores were calculated, and haplotypes were formed by inspection.


RESULTS
In the genome-wide scan, a maximum lod score of 2.89 was obtained for marker D19S414 on 19q13. Fine mapping using D19S931, D19S433, D19S928, D19S225, D19S416, D19S213, D19S425, and D19S220 markers from the Généthon database showed that markers in a 14.3-cM (12.66-Mb) interval flanked by D19S928 and D19S420 cosegregated with the cataract locus. Lack of homozygosity further suggests that the cataract locus may lie in a 7-cM (4.3-Mb) interval flanked by D19S928 proximally and D19S425 distally. On fine mapping, a maximum lod score of 3.09 was obtained with D19S416 at theta = 0.


CONCLUSIONS
Linkage analysis identified a new locus for autosomal recessive congenital nuclear cataracts on chromosome 19q13 in a consanguineous Pakistani family.
Riazuddin
S Amer
SA
Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-1860, USA.
Yasmeen
Afshan
A
Zhang
Qingjiong
Q
Yao
Wenliang
W
Sabar
Muhammad Farooq
MF
Ahmed
Zahoor
Z
Riazuddin
Sheikh
S
Hejtmancik
J Fielding
JF
D002386:Cataract / Q000235:genetics* / Q000473:pathology; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics*; D003241:Consanguinity; D005260:Female; D005808:Genes, Recessive; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D007907:Lens Nucleus, Crystalline / Q000473:pathology*; D008126:Lod Score; D008297:Male; D018895:Microsatellite Repeats; D010154:Pakistan; D010375:Pedigree; D016133:Polymerase Chain Reaction