Molecular Characteristics

Patients have compound heterozygous variants in the SEC24D gene that encodes protein transport protein Sec24D, which is a component of the coat protein complex II (COPII). COPII selects and exports cargo proteins from the endoplasmic reticulum (ER) to the Golgi complex. Type I and II collagen are included in these cargo proteins, thereby leading to skeletal disorders.
Diagnostic testing may include direct sequencing of the SEC24D gene or whole exome sequencing. In the 6 families reported thus far, 7 missense, 2 nonsense and 1 frameshift variants have been identified.