This document describes two types of achondrogenesis, a rare genetic disorder characterized by severe short-limb dwarfism and lack of bone development. Type I, also called Parenti-Fraccaro disease, involves a complete lack of bone formation in the skull, spine, and pelvis along with extremely short long bones. Type II, also called Langer-Saldino disease, allows for skull bone formation but not in the lower spine and pelvis, with short, stubby ribs that do not fracture. Both result in severe skeletal abnormalities and short stature.

1. ACHONDROGENESIS
Triad:
(l) Severe short-limb
dwarfism
(2) Lack of vertebral
calcification
(3) Large head with
normal I decreased
calvarial ossification

2. ACHONDROGENESIS
TYPE I= Parenti-Fraccaro disease
•Complete lack of
ossification of calvarium,
spine and pelvis.
•Absent sacrum and pubic
bone.
•Extremely short long
bones without bowing,
especially
•femur, radius, ulna.
•Thin ribs with multiple
fractures (frequent).

3. ACHONDROGENESIS
TYPE I= Parenti-Fraccaro disease
•Complete lack of
ossification of calvarium,
spine and pelvis.
•Absent sacrum and pubic
bone.
•Extremely short long
bones without bowing,
especially
•femur, radius, ulna.
•Thin ribs with multiple
fractures (frequent).

4. ACHONDROGENESIS
TYPE I= Parenti-Fraccaro disease
•Complete lack of
ossification of
calvarium, spine and
pelvis.
•Absent sacrum and
pubic bone.
•Extremely short long
bones without bowing,
especially
•femur, radius, ulna.
•Thin ribs with multiple
fractures (frequent).

5. ACHONDROGENESIS
TYPE II= Langer-Saldino disease
•Good ossification
of skull vault.
•Nonossification of
lower lumbar
vertebrae and
sacrum
•Short and stubby
horizontal ribs
without fractures

6. ACHONDROGENESIS
TYPE II= Langer-Saldino disease
•Good ossification
of skull vault.
•Nonossification of
lower lumbar
vertebrae and
sacrum
•Short and stubby
horizontal ribs
without fractures

7. ACHONDROGENESIS
•Irregular flared
metaphyses (esp.
humerus).
•Short trunk with
narrow chest and
protruding
abdomen.
•Redundant soft
tissues.
TYPE II= Langer-Saldino disease