The reticulum fails to .
differentiate into mature collagen or the collagen develops .
abnormally. This causes immature and coarse bone formation .
and thinning. (Loeb, 755).
SIGNS AND SYMPTOMS.
The signs and symptoms of OI vary greatly depending .
on the type. The most commonly used classification is the .
Sillence (type I to IV):.
Type I is the mildest form of OI and is inherited as .
an autosomal dominant trait. The sclerae(middle coat of .
eyeball) is distinctly blue. Type I is broken down into IA .
and IB -- the difference being whether dentinogenesis is .
present. IA has a life expectancy nearly the same as the .
general public. The physical activity is limited, and may .
appear to have no disability at all. The bones have a .
mottled or wormian appearance, forming small islands. .
(Isselbacher, 2111).
Type II is lethal in utero or shortly there .
afterbirth. The survivors live from just a few hours to .
several months. The kayotypes of parents are usually normal. .
This type is broken down into three subgroups: IIA is .
characterized by a broad, crumpled femora and continuos rib .
beading, IIB by minimal to no rib fractures, and IIC by a .
thin femora and ribs with extensive fracturing. While in .
the uterus, there is poor fetal movement, low fetal weight, .
poor ossification of the fetal skeleton, hypoplastic lungs, .
the long bones of the upper and lower limbs are shortened or .
deformed, and the head is soft. Intrauterine fractures .
occur, and parinatal death is usually from intracranial .
hemorrhage due to vessel fragility or respiratory distress .
from pulmonary hypoplasia. The bones and other tissues are .
extremely fragile, and massive injuries occur in utero or .
delivery. The ribs appear beaded or broken and the long .
bones crumpled. (Isselbacher, 2111).
Type III and IV are intermediate in severity between .
types I and II. Type III differs from I in its greater .
severity, and from IV in that it increases in severity with .