OMIM ID:
Glaucoma, Congenital Primary D
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Evidence of glaucoma can appear in early childhood but may appear much later. However, typical signs such as enlarged corneas or frank buphthalmos, cloudiness of the corneas, tearing and photophobia are present only when the pressure is elevated due to pupillary block or when the lens migrates into the anterior chamber. Most patients have additional signs such as ectopia lentis and spherophakia.
Systemic Features
Some patients have osteopenia, a high arched palate, and a marfanoid habitus.
Genetics
Inheritance
This form of congenital glaucoma has been described primarily in Middle Eastern and Asian as well as Roma/Gypsy families and is inherited in an autosomal recessive pattern. The mutations occur in the LTBP2 gene (14q24) which is in close proximity to GLC3C, another putative gene with mutations causing congenital glaucoma.
Mutations in other genes are also associated with primary congenital glaucoma such as in CYP1B1 causing type A (231300) and in GLC3B causing type B (600975).
THIS IS NOT A PRIMARY GLAUCOMA DISORDER. Microspherophakia and ectopia lentis are not features of primary congenital glaucoma. Elevated pressures in these patients are found only when there is a pupillary block or when the lens dislocates into the anterior chamber. The enlarged cornea is clear and has no breaks in the Descemet membrane. THIS CONDITION IS THEREFORE RECLASSIFIED AS “MEGALOCORNEA, ECTOPIA LENTIS, AND SPHEROPHAKIA”.
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.