DYNC2H1-related disorders are conditions that affect tiny hair-like structures on some cells called cilia. Cilia are important for the development of tissues like bones and cartilage, as well as organs like the eyes, kidneys, heart, pancreas, and intestines.
These disorders are part of a larger group called skeletal ciliopathies, which all involve problems with bone formation due to abnormal cilia. There are three types of DYNC2H1-related disorders: short-rib polydactyly syndrome, short-rib thoracic dysplasia, and chondroectodermal dysplasia (Ellis-van Creveld syndrome). While these types share some features, they differ in severity and outcomes.
Short-Rib Polydactyly Syndrome (SPRS): SPRS is the most severe form, where shortened ribs and a very narrow chest prevent the lungs from fully developing, which is often fatal at birth. Other symptoms include severe dwarfism, short hands, and extra fingers or toes. Birth defects in the heart, brain, palate, kidneys, and other organs may also be present.
Short-Rib Thoracic Dysplasia: This type, also known as Jeune syndrome, causes a narrow chest due to short ribs, with severity ranging from mild to severe. Dwarfism and small hands are common, but extra fingers are usually not. Children with this condition often develop cystic kidney disease and may have liver, pancreas, and vision problems.
Chondroectodermal Dysplasia (Ellis-van Creveld Syndrome): This type causes short ribs, a narrow chest, varying degrees of short limbs, and extra fingers and toes. People with this condition often have heart defects, and some may also have unusual fingernails, toenails, or teeth.
This group of conditions is caused by pathogenic (disease-causing) variants in the DYNC2H1 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance of having a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.
Resources:
Written August 2024
