Clinical phenotype and linkage analysis of the congenital fibrosis of the extraocular muscles in an Indian family.
OBJECTIVE
To describe the clinical phenotype and linkage analysis of the congenital fibrosis of the extraocular muscles (CFEOM) in an Indian family.


METHODS
Individuals were examined and their peripheral blood samples were withdrawn for genetic analysis. The disorder was tested for linkage to two known autosomal dominant CFEOM loci on chromosome 12p11.2-q12 (CFEOM1) and chromosome 16q24 (CFEOM3) using microsatellite markers.


RESULTS
Nine individuals including seven affecteds participated in the study. All seven affecteds had a classic form of CFEOM which included congenital bilateral ptosis, hypotropia, and chin elevation. The disorder segregated as an autosomal dominant trait in this family. The maximum simulated lod score in this family was 2.02. Linkage to CFEOM3 was excluded (Z<-2.00), whereas analysis of chromosome 12 markers was positive. The maximum observed two-point lod score was 1.8 (given the size and structure of the family) at theta=0 with marker D12S345. Markers D12S61, D12S1631, D12S87, D12S345, D12S59, D12S1048, and D12S1668 cosegregated with the disease locus in all affecteds. Haplotype analysis showed that the candidate region spanned the centromere.


CONCLUSIONS
The present data showed a classic CFEOM phenotype in an Indian family. The family's phenotype is consistent with linkage to CFEOM1 locus on chromosome 12p11.2-q12.
Venkatesh
C P
CP
Minto Eye Hospital, Bangalore, India.
Pillai
V S
VS
Raghunath
A
A
Prakash
V S
VS
Vathsala
R
R
Pericak-Vance
Margaret A
MA
Kumar
A
A
D001763:Blepharoptosis / Q000151:congenital / Q000235:genetics* / Q000473:pathology; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D005355:Fibrosis; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D007194:India; D008297:Male; D018895:Microsatellite Repeats; D009801:Oculomotor Muscles / Q000473:pathology*; D009886:Ophthalmoplegia / Q000151:congenital / Q000235:genetics* / Q000473:pathology; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D013285:Strabismus / Q000151:congenital / Q000235:genetics* / Q000473:pathology
D005819:Genetic Markers