0521779407-16 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:18
Osteogenesis Imperfecta 1097■Dentinogenesis imperfecta (DI) in 15% regardless of phenotype
➣“A” designation denotes DI absent, “B” indicates DI present
■Teeth fragile especially in children, brownish translucent quality
■Mixed sensory or conductive hearing loss appears 2nd-3rd decade
■Basilar invagination of the skull in severe cases: neurologic symp-
toms include headache, nerve compression, brain stem compres-
sion
Hydrocephalus in infants, etiology uncertain
■Scoliosis: more severe in types III and IV
■Joint hyperextensibility of digits, elbows and knees is mild
■Easy skin bruising, mild. Specific coagulation defect not defined.
Aortic and mitral insufficiency very infrequent
tests
Imaging
■Wormian bone (unmineralized cranial occipito-pareital islands) in
60% of infants or young children.
■Bone mineral density decreased by DXA. Accurate standards for chil-
dren being developed.
■Mild cases: normal overall bone architecture even after fractures, but
decreased cortical width and osteoporosis
■Severe cases: irregular fracture healing and skeletal deformities: Nar-
row or broad diaphyses in long bones
■Marked remodeling defect in II, III, IV: broad or narrow remodeling
defect
■Epiphyseal dysplasia with persistent whorls of calcified fibrous tissue
(“popcorn epiphysis”) in III, IV
■epiphyseal plate may be absent, accounting for growth defect Verte-
bral fractures may occur in children
■dentinogenesis imperfecta: coronal constriction, absent pulp space
■Test hearing in children and young adults
Biochemical Testing
■Standard blood tests including alkaline phosphatase normal except
after fracture
■Urine bone biomarker excretion (collagen crosslink, N-telopeptide,
pyridinoline crosslink) elevated in 20%: increased bone turnover in
children, low bone turnover in adults
■Hypercalciuria in approximately 15%: no clinical sequelae
■Renal calculi in a small percentage, independent of urine calcium
Pulmonary function studies
Sleep apnea in some type III/IV/V OI