Autosomal
recessively inherited osteogenesis imperfecta can be caused by mutations in the
following genes:
- CRTAP
(OI7)
- LEPRE1
(OI8)
- PPIB
(OI9)
-
SERPINH1 (OI10)
- FKBP10
(OI11)
- SP7
(OI12)
OI type
VII (OI7) is an autosomal recessive form of lethal OI. Multiple, recurrent
fractures are present at birth. Sclerae can be minimally bluish. Dentinogenesis
imperfecta, hearing loss, or ligamentous laxity are not described. Striking
radiographic findings can include rhizomelia and coxa vara. The head
circumference is small and eyes can show proptosis because of shallow orbits.
OI type
VIII (OI8) phenotype may overlap Sillence lethal type II/severe type III
osteogenesis imperfecta, with severe osteoporosis, shortened long bones, and a
soft skull with wide open fontanel. However, in contrast to the classic blue
sclerae, triangular face, and narrow thorax of severe and lethal osteogenesis
imperfecta, it is possible to have white sclerae, round face, and short
barrel-shaped chest. Bone density can be lower than almost all individuals with
severe osteogenesis imperfecta.
OI type
IX (OI9) can also resemble severe Sillence type II/III osteogenesis imperfecta.
It has been observed in children born from first-cousin parents. Shortened,
bowed, and fractured long bones without evidence of rhizomelia may be seen.
Weight and head circumference can be normal for gestational age. Bone histology
confirmes the diagnosis of OI. Gray-colored sclerae, flexed and abducted hips,
short bowed femurs with anterior bowing of the tibiae, and joint hypermobility,
especially of the finger and hip joints can be also seen. No evidence of
dentinogenesis imperfecta is reported.
OI type
X (OI10) is characterized by multiple bone deformities and fractures,
generalized osteopenia, dentinogenesis imperfecta, and blue sclera.
OI type
XI (OI11) were observed in consanguineous families from northern Turkey in
which a severe progressive deforming type of OI cosegregated with autosomal
recessive epidermolysis bullosa simplex, the latter resulting from a defect in
keratin-14. Dentinogenesis imperfecta was absent. The histologic features
included a distorted lamellar structure and a fish scale-like pattern, along
with elevated serum alkaline phosphatase. In other families, authors have
reported severe flexion deformity of knees, ankles, and, to a lesser extent,
elbows. Normal appearance of the sclera is reported. Patients with OI type XI
may have joint contractures.
OI type
XII (OI12) is characterized by recurrent fractures, mild bone deformations,
generalized osteoporosis, delayed teeth eruption, no dentinogenesis imperfecta,
normal hearing, and white sclerae.
