title: Non-syndromic posterior lenticonus a cause of childhood cataract: evidence for X-linked inheritance.
abstract: OBJECTIVE
  When an X-linked pedigree of posterior lenticonus with cataract was identified further evidence for X-linked inheritance of this condition was sought.
  
  
  METHODS
  Forty-three cases of posterior lenticonus were identified from a database of 354 children with cataract. Two children with the X-linked syndromes of Lowe and Nance-Horan and 3 children with Fanconi syndrome have been excluded from further analysis. None of the children was deaf. None of the non-syndromic cases had microcornea.
  
  
  RESULTS
  There were 38 cases of non-syndromic posterior lenticonus (approximately 11%). There were 15 children from 13 pedigrees and 23 apparently sporadic cases. Of the 106 cases on the database with unilateral cataract 15 had posterior lenticonus (approximately 14%). Eleven of 13 pedigrees were compatible with X-linked inheritance or autosomal dominant inheritance with variable expression. However, in 2 pedigrees there was father to son transmission.
  
  
  CONCLUSIONS
  Posterior lenticonus is a common cause of unilateral infantile cataract, but is thought to be a rare cause of bilateral cataracts. This study suggests that posterior lenticonus is responsible for a significant proportion of childhood cataracts (approximately 14% of unilateral and approximately 9% of bilateral cases). Posterior lenticonus is generally thought to occur as a sporadic condition. This study demonstrates that there is a family history of early-onset cataract in a significant number of bilateral cases (approximately 58%).
authors.affiliation: Great Ormond Street Hospital for Children, London, UK. isabelle.re@dial.pipex.com
authors.forename: I M
authors.initials: IM
authors.lastname: Russell-Eggitt
mesh_terms: D000293:Adolescent; D000328:Adult; D002386:Cataract / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007903:Lens Capsule, Crystalline / Q000473:pathology*; D008297:Male; D010375:Pedigree; D013577:Syndrome; D014960:X Chromosome