Table 1.

Novel gene subtypes of osteogenesis imperfecta. Adapted from Forlino and Marini.¹

Type	Inheritance	Mutation	Protein	Disease mechanism	Skeletal phenotype	Associated features
Ι	AD	COL1A/2	Collagen type 1, α1/2	Collagen synthesis/processing	Mild–moderate	DI, blue sclera, deafness
ΙΙ	AD				Lethal	Pulmonary hypoplasia
ΙΙΙ	AD				Severe
ΙV	AD				Moderate	DI, basilar invagination
V	AD	IFITM5	Interferon-induced transmembrane protein 5	Mineralization defect	Moderate	Hyperplastic callous formation
VΙ	AR	SEPINF1	Pigment epithelium-derived factor	Mineralization defect	Moderate–severe	‘Fish scale’ pattern on iliac crest biopsies
VΙΙ	AR	CRTAP	Cartilage-associated protein	Collagen modification	Severe–lethal	Similar to ΙV, rhizomelia
VΙΙΙ	AR	LEPRE1	Leucine proline-enriched proteoglycan 1/prolyl 3-hydroxylase 1	Collagen modification	Severe–lethal	Platyspondyly, scoliosis
ΙX	AR	PPIB	Peptidylprolyl isomerase B/cyclophilin B	Collagen modification	Severe	Short stature
X	AR	SERPINH1	Serpin peptidase inhibitor	Chaperone defect collagen folding	Severe	Nephrolithiasis
XΙ	AR	FKBP10	FK506 binding protein 65	Chaperone defect collagen folding	Moderate–severe	Congenital contractures
XΙΙ	AR	SP7	Transcription factor 7	Osteoblast development	Moderate	Midface hypoplasia
XΙΙΙ	AR	BMP1	Bone morphogenic protein 1	Collagen synthesis/processing	Mild–severe	Umbilical hernia
XΙV	AR	TNEM38B	Transmembrane protein 38 B	Collagen modification	Severe
XV	AR	WNT1	Wingless-type member 1	Osteoblast development	Moderate–severe	Neurological deficits
XVΙ	AR	CREB3L1	CAMP responsive element binding	Osteoblast development	Severe

AD, autosomal dominant; AR, autosomal recessive.