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.