<unk>  type 2 has an autosomal dominant inheritance pattern, not to be confused with the autosomal recessive<unk>  type 1. The mutations responsible for<unk> 2 are thought to be a result of heterozygous mutations, or compound heterozygosity; specifically, it is thought to be caused by the substitution or deletion of single amino acids that are phylogenetically conserved in the FAM111A gene. The FAM111A gene is located at 11q12.1 and mutations of the gene are not only responsible for<unk> 2, but also Gracile bone dysplasia (osteocraniostenosis). The gene FAM111A codes for a 611 amino acid protein that resembles a trypsin-like-peptidase, but the protein's native function is unknown. What is apparent, however, is that FAM111A codes for a protein that is crucial to pathways that govern parathyroid hormone production, calcium homeostasis, and skeletal development and growth. Very little is known about differing severities of<unk> s because of the very limited number of affected individuals, but it is known that OCS and<unk> 2 have different severities and they result from mutations at the same locus.
Kenny-Caffey syndrome
Cohen syndrome
Cohen-Gibson syndrome
Gleich's syndrome
De Barsy syndrome
Foster Kennedy syndrome
Leschke syndrome
Fox–Fordyce disease