Stickler Syndrome, Type IV

Clinical Characteristics
Ocular Features: 

Evidence of vitreoretinal degeneration is common and the risk of retinal detachment is high.  High myopia is common.  Cataracts are not a feature in contrast to types I and II Stickler syndrome.

It is likely that the ocular phenotype will be expanded with the report of additional families.

Systemic Features: 

Sensorineural hearing loss and short stature are often present. The latter is not usually a feature in other types of Stickler syndrome.  However, midface hypoplasia and micrognathia may be present in all types as well as in Marshall syndrome.  Midline clefting usually does not occur.

Genetics

A reported pedigree suggests autosomal recessive inheritance based on parental consanguinity and the lack of parent-to-child transmission.  Affected individuals have homozygous deletion mutations leading to loss of function in COL9A2 (1p33-p32) while parents are heterozygous.  A family with mutations in COL9A1 (6q12-q14), usually causing multiple epiphyseal dysplasia, has been reported to have autosomal recessive Stickler syndrome as well.  Homozygous individuals had typical ocular and auditory findings of autosomal dominant Stickler syndrome but with evidence of epiphyseal dysplasia.

Type I Stickler syndrome (108300, 609508) is an autosomal dominant disorder with somewhat similar ocular manifestations resulting from mutations in COL2A1.

Type II Stickler syndrome (604841) with a somewhat similar ocular phenotype is also an autosomal dominant disorder but caused by mutations in COL11A1.

Treatment
Treatment Options: 

The myopia and hearing loss can be corrected.  Lifelong vigilance and prompt treatment are required for the vitreoretinal disease.

References
Article Title: 

References

Baker S, Booth C, Fillman C, Shapiro M, Blair MP, Hyland JC, Ala-Kokko L. A loss of function mutation in the COL9A2 gene causes autosomal recessive Stickler syndrome. Am J Med Genet A. 2011 Jul;155(7):1668-72.

PubMedID: 21671392

Van Camp G, Snoeckx RL, Hilgert N, van den Ende J, Fukuoka H, Wagatsuma M, Suzuki H, Smets RM, Vanhoenacker F, Declau F, Van de Heyning P, Usami S. A new autosomal recessive form of Stickler syndrome is caused by a mutation in the COL9A1 gene. Am J Hum Genet. 2006 Sep;79(3):449-57.

PubMedID: 16909383