PURPOSE: The purpose of the study was to look for ADAMTSL4 mutations in a cohort 
of German patients with isolated ectopia lentis from nonconsanguineous families.
METHODS: Mutation screening was performed by PCR amplification of the coding 
exons of ADAMTSL4 and subsequent sequencing.
RESULTS: An identical homozygous deletion of 20 bp of coding sequence within 
exon 6 (NM_019032.4:c.759_778del20) was identified in eight individuals from 
seven unrelated families. In a screen of 360 ethnically matched, unaffected 
individuals, two heterozygous mutation carriers were found. The mutation was 
always accompanied by the identical haplotype, suggestive of a founder mutation.
CONCLUSIONS: The results emphasize the association of ADAMTSL4 null mutations 
with isolated ectopia lentis and the presence of a founder mutation in the 
European population. Screening of ADAMTSL4 should be considered in all patients 
with isolated ectopia lentis, with or without family history. In patients from 
nonconsanguineous families, the authors propose a two-step diagnostic approach, 
starting with an examination of exon 6 before sequencing the entire coding 
region of ADAMTSL4.