Clinical Characteristics
Ocular Features
Megalocornea, congenital glaucoma, a concave iris with stromal atrophy and corectopia, and deep anterior chambers are typical ocular features. High myopia has been reported and retinal detachments have been observed. Glaucoma control can be difficult to achieve and there is a significant risk of cataracts and phthisis bulbi following surgery. Posterior embryotoxon has not been observed.
Systemic Features
Facial features seem to be consistent. The forehead is wide, the nose appears broad with a large nasal tip and broad nares although the bridge appears narrow. The philtrum is long and wide. The ears may appear large and the neck is short. The thorax is abnormally wide and the nipples are widely spaced and umbilicated. The long bones are slender with thin cortices and wide metaphyses. There is generalized osteopenia. Vertebral bodies are cuboid-shaped with narrow vertebral canals and enlarged apophyses
Genetics
Inheritance
Two non-consanguineous families each with 3 sibs have been reported suggesting autosomal recessive inheritance. Nothing is known about the mutation or its locus.
The ocular features may resemble Rieger or Axenfeld anomaly but these are inherited in autosomal dominant patterns and the skeletal features are dissimilar.
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.