OMIM ID:
Joint Laxity, Short Stature, and Myopia
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Three of four brothers in one family had high myopia and two had retinal detachments as well as iris and chorioretinal colobomas. In a second family with five sibs a teenage female was reported to have glaucoma and vision of legal blindness. She and one brother had high myopia as well (parameters not reported).
Systemic Features
In one consanguineous family a brother and sister had multiple large joint dislocations including elbows, hips, knees and ankles. The sister exhibited severe kyphoscoliosis while her brother had only mild kyphosis. A single individual in each of the two sibships had hearing loss.
Three brothers in another consanguineous family had joint laxity and mild pectus carinatum.
Short stature was noted in all 5 affected individuals. Cognitive development was reported as normal.
Genetics
Inheritance
Five individuals from 2 consanguineous Saudi sibships have been reported. Homozygous mutations in the GZF1 gene (20p11.21) segregated as expected for an autosomal recessive disorder.
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.