Clinical Characteristics
Ocular Features
Most dislocated lenses of non-traumatic origin are associated with syndromes, particularly those with defective connective tissue. However, a few families with dislocated lenses have been reported in which no evidence of defective collagen is present. The lens is most commonly displaced temporally, often creating myopic astigmatism. The mean age of discovery of the dislocated lenses is about 2 years of age. The eye is otherwise normally formed, intraocular pressure is normal, and the axial length is in the normal range. The cornea, pupil, and iris are normal unlike that found in many patients with ectopia lentis et pupillae (225200).
Systemic Features
None by definition.
Genetics
Inheritance
Homozygous nonsense mutations in ADAMTSL4 (1q21.3) are responsible for this autosomal recessive condition. The same gene is mutated in ectopia lentis et pupillae (225200). A patient has been reported with craniosynostosis and ectopia lentis in which there was a homozygous 20 bp deletion in this gene.
An autosomal dominant condition of isolated dislocated lenses (129600) secondary to a mutation in FBN1 has also been reported.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.