Genetics Home Reference :
25
Gnathodiaphyseal dysplasia is a disorder that affects the bones. People with this condition have reduced bone mineral density (osteopenia), which causes the bones to be unusually fragile. As a result, affected individuals typically experience multiple bone fractures in childhood, often from mild trauma or with no apparent cause.
While most bone tissue is less dense than normal in gnathodiaphyseal dysplasia, the outer layer (cortex) of the shafts of the long bones in the arms and legs is abnormally hard and thick (diaphyseal sclerosis). Bowing of the long bones also occurs in this disorder.
Jaw problems are common in gnathodiaphyseal dysplasia; the prefix "gnatho-" in the condition name refers to the jaw. Affected individuals may develop bone infections (osteomyelitis) in the jaw, which can lead to pain, swelling, discharge of pus from the gums, loose teeth, and slow healing after teeth are lost or extracted. Areas of the jawbone may lose the protective coverage of the gums, which can result in deterioration of the exposed bone (osteonecrosis of the jaw). Also, normal bone in areas of the jaw may be replaced by fibrous tissue and a hard material called cementum, which normally surrounds the roots of teeth and anchors them in the jaw. These areas of abnormal bone, called cementoosseous lesions, may be present at birth or develop later in life.
When gnathodiaphyseal dysplasia was first described, it was thought to be a variation of another bone disorder called osteogenesis imperfecta, which is also characterized by frequent bone fractures. However, gnathodiaphyseal dysplasia is now generally considered to be a separate condition. Unlike in osteogenesis imperfecta, the fractures in gnathodiaphyseal dysplasia heal normally without causing deformity or loss of height.
MalaCards based summary :
Gnathodiaphyseal Dysplasia, also known as
gdd, is related to
fibrous dysplasia and
osteomyelitis. An important gene associated with Gnathodiaphyseal Dysplasia is
ANO5 (Anoctamin 5). Affiliated tissues include
bone and
cortex, and related phenotypes are
bowing of the long bones and
broad jaw
Disease Ontology :
12
An osteochondrodysplasia characterized by cementoosseous lesions of the jawbones, bone fragility, bowing/cortical thickening of tubular bones, and diaphyseal sclerosis of long bones that has material basis in heterozygous mutation in ANO5 on chromosome11p14.3.
NIH Rare Diseases :
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The following summary is from Orphanet , a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 53697 Definition Gnathodiaphyseal dysplasia (GDD) is a bone dysplasia characterized by bone fragility, frequent bone fractures at a young age, cemento-osseous lesions of the jaw bones, bowing of tubular bones (tibia and fibula) and diaphyseal sclerosis of long bones associated with generalized osteopenia. GD follows an autosomal dominant mode of transmission. Visit the Orphanet disease page for more resources.
OMIM :
56
Gnathodiaphyseal dysplasia is an autosomal dominant generalized skeletal syndrome characterized by cementoosseous lesions of the jawbones, in conjunction with bone fragility, bowing/cortical thickening of tubular bones, and diaphyseal sclerosis of long bones (summary by Marconi et al., 2013).
(166260)
KEGG :
36
Gnathodiaphyseal dysplasia is a rare skeletal syndrome with autosomal dominant inheritance. It is characterized by cemento-osseous lesions of the jawbone, bone fragility, and sclerosis of tubular bones. Missense mutations of GDD1, which shows homology to TMEM16E, were identified.
UniProtKB/Swiss-Prot :
73
Gnathodiaphyseal dysplasia: Rare skeletal syndrome characterized by bone fragility, sclerosis of tubular bones, and cemento-osseous lesions of the jawbone. Patients experience frequent bone fractures caused by trivial accidents in childhood; however the fractures heal normally without bone deformity. The jaw lesions replace the tooth-bearing segments of the maxilla and mandible with fibrous connective tissues, including various amounts of cementum-like calcified mass, sometimes causing facial deformities. Patients also have a propensity for jaw infection and often suffer from purulent osteomyelitis-like symptoms, such as swelling of and pus discharge from the gums, mobility of the teeth, insufficient healing after tooth extraction and exposure of the lesions into the oral cavity.
Rare bone diseases 
