Stickler Syndrome, Type Iv

A number sign (#) is used with this entry because of evidence that Stickler syndrome type IV (STL4) is caused by homozygous mutation in the COL9A1 gene (120210) on chromosome 6q13.

For a general phenotypic description and a discussion of genetic heterogeneity of Stickler syndrome, see 108300.

Clinical Features

Van Camp et al. (2006) described a consanguineous Moroccan family in which 4 of 10 sibs had features characteristic of Stickler syndrome, including moderate to severe sensorineural hearing loss, moderate to high myopia with vitreoretinopathy, and epiphyseal dysplasia.

Nikopoulos et al. (2011) reported 2 sisters in a Turkish family and 1 boy in a Moroccan family with features of autosomal recessive Stickler syndrome. All 3 individuals had myopia, vitreous changes, sensorineural hearing loss, and epiphyseal dysplasia. They also had exudative rhegmatogenous retinal detachment.

Inheritance

Stickler syndrome IV has an autosomal recessive inheritance pattern (Van Camp et al., 2006).

Molecular Genetics

In 4 sibs with Stickler syndrome, offspring of healthy, consanguineous Moroccan parents, Van Camp et al. (2006) identified a homozygous nonsense mutation (R295X; 120210.0002) in the COL9A1 gene. The parents and 4 other sibs were heterozygous for the mutation, and 2 other sibs were homozygous for the wildtype allele.

In affected members of 2 consanguineous families segregating autosomal recessive Stickler syndrome, Nikopoulos et al. (2011) identified homozygous mutations in the COL9A1 gene. One affected boy in a Moroccan family was homozygous for the R295X mutation, and 2 affected sisters in a Turkish family were homozygous for a novel nonsense mutation (R507X; 120210.0003).