Japanese patient with Cole‐carpenter syndrome with compound heterozygous variants of SEC24D

Cole‐Carpenter syndrome is a rare skeletal dysplasia associated with low‐bone mass or an osteogenesis imperfecta (OI)‐like syndrome. Only 3 and 6 variants in SEC24D have been reported in patients with Cole‐Carpenter syndrome type 2 and autosomal recessive OI, respectively. We describe a 15‐year‐old Japanese boy with short stature of the short‐trunk type and craniofacial abnormalities including ocular proptosis, marked frontal bossing, midface hypoplasia, and micrognathia. These features were consistent with a diagnosis of Cole‐Carpenter syndrome. He had low‐bone mineral density and basilar impression. Whole exome sequencing analysis identified biallelic variants in SEC24D (p.Arg484* and p.Arg313His) in the patient. We will report a patient with compound heterozygous variants of SEC24D causing Cole‐Carpenter syndrome type 2.