Knobloch syndrome

What causes Knobloch syndrome?

Some cases of Knobloch syndrome are caused by mutations in the COL18A1 gene. This gene provides instructions for making a protein that is used to assemble type XVIII collagen. Collagens are a family of proteins that strengthen and support connective tissues, such as skin, bone, tendons, and ligaments, throughout the body. The condition has also been linked to a specific region on chromosome 17, known as 17q11.2. However, researchers have not determined which gene in this region is associated with Knobloch syndrome.

Last updated on 05-01-20

How is Knoblch syndrome inherited?

Knobloch syndrome has an autosomal recessive pattern of inheritance, which means that both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they do not show signs and symptoms of the condition. When 2 carriers of an autosomal recessive condition have children, each cild has a:

  • 25% chance to be affected
  • 50% chance to be an unaffected carrier like each parent
  • 25% chance to be unaffected and not a carrier

Last updated on 05-01-20

What is Knobloch syndrome?

Knobloch syndrome is characterized by severe vision problems and skull defects. The most common features include extreme nearsightedness (high myopia), recurrent retinal detachment, and occipital encephalocele. There are three types of Knobloch syndrome, which can be distinguished by the underlying genetic cause. Knobloch syndrome type I is caused by mutations in the COL18A1 gene. The genes associated with Knobloch syndrome type 2 and type 3 have not been identified; however, Knobloch syndrome type 3 has been linked to a specific region on chromosome 17, known as 17q11.2. Knobloch syndrome follows an autosomal recessive pattern of inheritance. Treatment is aimed at addressing the symptoms present in each individual and may include surgery to repair retinal detachments and occiptal encephaloceles.

Last updated on 05-01-20

How did Knobloch syndrome get its name?

Knobloch syndrome is named after one of the authors who first published an article on this condition. In 1971, a family was described by W.H. Knobloch and J.M. Layer in which 5 of 10 siblings had severe nearsightedness (myopia), recurrent retinal detachment, and encephalocele. All of the affected siblings had normal intelligence. The parents were unaffected and were not related to one another.

Last updated on 05-01-20

Name: National Alliance for Eye and Vision Research (NAEVR) 1801 Rockville Pike, Suite 400
Rockville, MD, 20852, United States
Phone: 240-221-2905 Fax : 240-221-0370 Email: Url:
Name: Foundation Fighting Blindness 7168 Columbia Gateway Drive, Suite 100
Columbia, MD, 21046, United States
Phone: +1-410-423-0600 TTY: 1-800-683-5551 Toll Free: 1-800-683-5555 Email: Url:
Name: Retina International Ausstellungsstr. 36 8005 Zurich
Phone: + 41 (0)44 444 10 77 Email: Url:

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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