OMIM ID:
Spherophakia, Isolated
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Small, spherical lenses are characteristic of this entity. Lenticular myopia is usually present but no increased axial length. Glaucoma has been reported in several individuals and speculated to be due to pupillary block. No buphthalmos or angle anomalies were present. The lens may sublux into the vitreous cavity.
Systemic Features
No skeletal, cardiovascular or metabolic disease is present.
Genetics
Inheritance
Isolated spherophakia is an autosomal recessive disorder resulting from homozygous mutations in LTBP2 (13q24.1-q32.12). Parental consanguinity was present in reported families.
Spherophakia is a clinically and genetically heterogeneous disorder and usually found in association with systemic findings. It is commonly seen in the Weill-Marchesani syndrome 1 (277600), in Weill Marchesani syndrome 2 (608328), in the Weill-Marchesani-Like syndrome (613195), in a condition known as ‘megalocornea, ectopia lentis, and spherophakia’ (?), another one called 'spherophakia and hernia' (157150), sulfite oxidase deficiency (272300), primary congenital glaucoma D (613086) and in a syndrome known as ‘spherophakia and metaphyseal dysplasia’ (157151).
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.