# Generalised skeletal dysplasias

Generalised skeletal dysplasias

Achondroplasia Achondroplasia is caused by a gain-in-function mutation in the FGFR3 (fibroblast growth factor receptor 3) gene, located on the short arm of  chromosome (Chr) 4, which a ff ects enchondral bone formation. It is autosomal dominant. Patients present with disproportionate short stature where the limbs are shorter than the trunk, together with classical clinical and radiographic features ( Figure 44.7 ). Underdevelopment of the foramen magnum and spinal stenosis can cause neurological di ffi culties. Correction of  limb alignment may be necessary and limb-lengthening techniques are used in some countries. Hereditary multiple exostoses An autosomal dominant condition related to a loss-of function mutation in either the EXT1 (Chr 8q) or gene (Chr 11p), leads to dysregulated growth and exostosis formation. Exostoses consisting of  a cartilaginous cap on a bony stalk may be sessile or pedunculated. They grow as the child grows and may cause cosmetic or functional di ffi culties, - EXT2 

Figure 44.5
A child with arthrogryposis multiplex congenita and
featureless upper limbs (no skin creases or muscle de
/f_i
nition). He
mobilises with the help of knee–ankle–foot orthoses.
Figure 44.6
Radiograph of
a child born with proximal
femoral focal de
/f_i
ciency.
A proximal femoral oste
-
otomy improved her hip
mechanics and stability
(a screw has come loose
from the plate). She opted
to keep her foot and not to
undergo leg lengthening.
She functions well with an
extension prosthesis.

bones of  the forearm and lower leg can lead to joint deformity and dislocation of  the radial head, exacerbated by the e ff ects Louis Xavier Edouard Léopold Ollier , 1830–1900, Professor of  Surgery , Lyons, France, described enchondromatosis in 1899. Angelo Ma ff ucci , 1845–1903, Professor of  Pathological Anatomy , Pisa, Italy , described enchondromatosis in association with soft-tissue haemangiomas in 1881. Donovan James McCune , 1902–1976, American paedia trician. Fuller Albright , 1900–1969, physician, Massachusetts General Hospital, Boston, MA, USA. prevent deformity ( Figure 44.8 ). Continued growth after skeletal maturity may represent malignant transformation of a benign osteochondroma: a rare occurrence (see Chapter 42 ). Enchondromatosis (Ollier’s disease) Enchondromas arise from chondrocyte rests within the medul - lary canal of  tubular bones: they consist of  mature hyaline cartilage ( Figure 44.9 ). Larger lesions may show calcification on radiographs and vertical lucent streaks (representing cartilage columns) in the metaphysis. Pathological fractur es are common. In Ma ff ucci’s syndrome there are also soft-tissue haemangiomas and lymphangiomas (see Chapter 42 ). Fibrous dysplasia This common disorder is often a chance radiographic finding, particularly in its monostotic form. It is a localised defect in osteoblastic di ff erentiation and maturation in which normal bone is replaced by fibrous stroma. With polyostotic fibrous dysplasia, limb deformity and pathological fractures are common. In patients with precocious puberty and Coast of Maine café-au-lait spots, the diagnosis is McCune–Albright syndrome ( Figure 44.10 ). Summary box 44.3 Congenital and developmental abnormalities of the skeleton /uni25CF /uni25CF /uni25CF 

(a)
(b)
Figure 44.7
Achondroplasia.
(a)
A child with achondroplasia: his upper
limbs are short and his hands do not reach midthigh.
(b)
Standing leg
length/alignment radiograph of a different child demonstrating short
limbs, widened metaphysis, an overlong
/f_i
bula and slight bowing. The
acetabulum is horizontal and the pelvic wings seem square: classical
features of achondroplasia.
Achondroplasia affects enchondral ossi
/f_i
cation and presents
with disproportionate short stature
Exostoses may cause functional and/or cosmetic problems
Patients with Ollier’s disease (multiple enchondromatosis)
often have lesions in the hands and feet
Figure 44.8
Radiograph of the knee showing multiple broad-based
osteochondromas.



Figure 44.9
Anteroposterior radiograph of the index
/f_i
nger of a child
showing a solitary enchondroma (arrow): note the opacity in the soft
tissues, which represents the extent of the cartilaginous lesion.

Generalised skeletal dysplasias

Achondroplasia Achondroplasia is caused by a gain-in-function mutation in the FGFR3 (fibroblast growth factor receptor 3) gene, located on the short arm of  chromosome (Chr) 4, which a ff ects enchondral bone formation. It is autosomal dominant. Patients present with disproportionate short stature where the limbs are shorter than the trunk, together with classical clinical and radiographic features ( Figure 44.7 ). Underdevelopment of the foramen magnum and spinal stenosis can cause neurological di ffi culties. Correction of  limb alignment may be necessary and limb-lengthening techniques are used in some countries. Hereditary multiple exostoses An autosomal dominant condition related to a loss-of function mutation in either the EXT1 (Chr 8q) or gene (Chr 11p), leads to dysregulated growth and exostosis formation. Exostoses consisting of  a cartilaginous cap on a bony stalk may be sessile or pedunculated. They grow as the child grows and may cause cosmetic or functional di ffi culties, - EXT2 

Figure 44.5
A child with arthrogryposis multiplex congenita and
featureless upper limbs (no skin creases or muscle de
/f_i
nition). He
mobilises with the help of knee–ankle–foot orthoses.
Figure 44.6
Radiograph of
a child born with proximal
femoral focal de
/f_i
ciency.
A proximal femoral oste
-
otomy improved her hip
mechanics and stability
(a screw has come loose
from the plate). She opted
to keep her foot and not to
undergo leg lengthening.
She functions well with an
extension prosthesis.

bones of  the forearm and lower leg can lead to joint deformity and dislocation of  the radial head, exacerbated by the e ff ects Louis Xavier Edouard Léopold Ollier , 1830–1900, Professor of  Surgery , Lyons, France, described enchondromatosis in 1899. Angelo Ma ff ucci , 1845–1903, Professor of  Pathological Anatomy , Pisa, Italy , described enchondromatosis in association with soft-tissue haemangiomas in 1881. Donovan James McCune , 1902–1976, American paedia trician. Fuller Albright , 1900–1969, physician, Massachusetts General Hospital, Boston, MA, USA. prevent deformity ( Figure 44.8 ). Continued growth after skeletal maturity may represent malignant transformation of a benign osteochondroma: a rare occurrence (see Chapter 42 ). Enchondromatosis (Ollier’s disease) Enchondromas arise from chondrocyte rests within the medul - lary canal of  tubular bones: they consist of  mature hyaline cartilage ( Figure 44.9 ). Larger lesions may show calcification on radiographs and vertical lucent streaks (representing cartilage columns) in the metaphysis. Pathological fractur es are common. In Ma ff ucci’s syndrome there are also soft-tissue haemangiomas and lymphangiomas (see Chapter 42 ). Fibrous dysplasia This common disorder is often a chance radiographic finding, particularly in its monostotic form. It is a localised defect in osteoblastic di ff erentiation and maturation in which normal bone is replaced by fibrous stroma. With polyostotic fibrous dysplasia, limb deformity and pathological fractures are common. In patients with precocious puberty and Coast of Maine café-au-lait spots, the diagnosis is McCune–Albright syndrome ( Figure 44.10 ). Summary box 44.3 Congenital and developmental abnormalities of the skeleton /uni25CF /uni25CF /uni25CF 

(a)
(b)
Figure 44.7
Achondroplasia.
(a)
A child with achondroplasia: his upper
limbs are short and his hands do not reach midthigh.
(b)
Standing leg
length/alignment radiograph of a different child demonstrating short
limbs, widened metaphysis, an overlong
/f_i
bula and slight bowing. The
acetabulum is horizontal and the pelvic wings seem square: classical
features of achondroplasia.
Achondroplasia affects enchondral ossi
/f_i
cation and presents
with disproportionate short stature
Exostoses may cause functional and/or cosmetic problems
Patients with Ollier’s disease (multiple enchondromatosis)
often have lesions in the hands and feet
Figure 44.8
Radiograph of the knee showing multiple broad-based
osteochondromas.



Figure 44.9
Anteroposterior radiograph of the index
/f_i
nger of a child
showing a solitary enchondroma (arrow): note the opacity in the soft
tissues, which represents the extent of the cartilaginous lesion.

Generalised skeletal dysplasias

Achondroplasia Achondroplasia is caused by a gain-in-function mutation in the FGFR3 (fibroblast growth factor receptor 3) gene, located on the short arm of  chromosome (Chr) 4, which a ff ects enchondral bone formation. It is autosomal dominant. Patients present with disproportionate short stature where the limbs are shorter than the trunk, together with classical clinical and radiographic features ( Figure 44.7 ). Underdevelopment of the foramen magnum and spinal stenosis can cause neurological di ffi culties. Correction of  limb alignment may be necessary and limb-lengthening techniques are used in some countries. Hereditary multiple exostoses An autosomal dominant condition related to a loss-of function mutation in either the EXT1 (Chr 8q) or gene (Chr 11p), leads to dysregulated growth and exostosis formation. Exostoses consisting of  a cartilaginous cap on a bony stalk may be sessile or pedunculated. They grow as the child grows and may cause cosmetic or functional di ffi culties, - EXT2 

Figure 44.5
A child with arthrogryposis multiplex congenita and
featureless upper limbs (no skin creases or muscle de
/f_i
nition). He
mobilises with the help of knee–ankle–foot orthoses.
Figure 44.6
Radiograph of
a child born with proximal
femoral focal de
/f_i
ciency.
A proximal femoral oste
-
otomy improved her hip
mechanics and stability
(a screw has come loose
from the plate). She opted
to keep her foot and not to
undergo leg lengthening.
She functions well with an
extension prosthesis.

bones of  the forearm and lower leg can lead to joint deformity and dislocation of  the radial head, exacerbated by the e ff ects Louis Xavier Edouard Léopold Ollier , 1830–1900, Professor of  Surgery , Lyons, France, described enchondromatosis in 1899. Angelo Ma ff ucci , 1845–1903, Professor of  Pathological Anatomy , Pisa, Italy , described enchondromatosis in association with soft-tissue haemangiomas in 1881. Donovan James McCune , 1902–1976, American paedia trician. Fuller Albright , 1900–1969, physician, Massachusetts General Hospital, Boston, MA, USA. prevent deformity ( Figure 44.8 ). Continued growth after skeletal maturity may represent malignant transformation of a benign osteochondroma: a rare occurrence (see Chapter 42 ). Enchondromatosis (Ollier’s disease) Enchondromas arise from chondrocyte rests within the medul - lary canal of  tubular bones: they consist of  mature hyaline cartilage ( Figure 44.9 ). Larger lesions may show calcification on radiographs and vertical lucent streaks (representing cartilage columns) in the metaphysis. Pathological fractur es are common. In Ma ff ucci’s syndrome there are also soft-tissue haemangiomas and lymphangiomas (see Chapter 42 ). Fibrous dysplasia This common disorder is often a chance radiographic finding, particularly in its monostotic form. It is a localised defect in osteoblastic di ff erentiation and maturation in which normal bone is replaced by fibrous stroma. With polyostotic fibrous dysplasia, limb deformity and pathological fractures are common. In patients with precocious puberty and Coast of Maine café-au-lait spots, the diagnosis is McCune–Albright syndrome ( Figure 44.10 ). Summary box 44.3 Congenital and developmental abnormalities of the skeleton /uni25CF /uni25CF /uni25CF 

(a)
(b)
Figure 44.7
Achondroplasia.
(a)
A child with achondroplasia: his upper
limbs are short and his hands do not reach midthigh.
(b)
Standing leg
length/alignment radiograph of a different child demonstrating short
limbs, widened metaphysis, an overlong
/f_i
bula and slight bowing. The
acetabulum is horizontal and the pelvic wings seem square: classical
features of achondroplasia.
Achondroplasia affects enchondral ossi
/f_i
cation and presents
with disproportionate short stature
Exostoses may cause functional and/or cosmetic problems
Patients with Ollier’s disease (multiple enchondromatosis)
often have lesions in the hands and feet
Figure 44.8
Radiograph of the knee showing multiple broad-based
osteochondromas.



Figure 44.9
Anteroposterior radiograph of the index
/f_i
nger of a child
showing a solitary enchondroma (arrow): note the opacity in the soft
tissues, which represents the extent of the cartilaginous lesion.