OMIM ID:
Spondyloocular Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Cataracts have been noted in several patients in the first and second decades of life. Nystagmus and ‘amblyopia’ have also been reported. Several individuals have had retinal detachments.
Systemic Features
Only a small number of families have been reported. Poor bone mineralization with frequent fractures in long bones and vertebral compression seem to be consistent features often noted in the first and second decades of life. Moderate osteoporosis and advanced bone age with platyspondyly may be present. The vertebral fractures lead to abnormal spinal curvature and may result in shortened stature.
Some sensorineural hearing loss is sometimes detected in the first decade. The ears have been described as low-set and posteriorly rotated. A variety of cardiac defects have been reported including mitral valve prolapse, septal defects, and anomalies of the aortic valve.
Genetics
Inheritance
This is an autosomal recessive disorder secondary to homozygous mutations in the XYLT2 gene located at 17q21.33.
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.