Slipped capital femoral epiphysis is defined as a posterior and inferior slippage of the proximal epiphysis of the femur onto the metaphysis (femoral neck), occurring through the physeal plate during the early adolescent growth spurt.

Mild spondyloepiphyseal dysplasia due to COL2A1 mutation with early-onset osteoarthritis is a type 2 collagen-related bone disorder characterized by precocious, generalized osteoarthritis (with onset as early as childhood) and mild, dysplastic spinal changes (flattening of vertebrae, irregular endplates and wedge-shaped deformities) resulting in a mildly short trunk.

A form of acromelic dysplasia with the distinctive radiological sign of angel-shaped middle phalanges, a typical metacarpophalangeal pattern profile (mainly affecting first metacarpals and middle phalanges of second, third and fifth digits which all appear short), epiphyseal changes in the hips and in some, abnormal dentition and delayed bone age. A rare disease with less than 20 cases reported in the literature, however, it is likely under diagnosed. Caused by mutations in the growth differentiation factor 5 (GDF5) gene, located on chromosome 20q11.2, encoding CDMP1 (cartilage derived morphogenetic protein). CDMP1 belongs to the TGF beta super family and plays a role in bone growth and joint morphogenesis. Transmitted as an autosomal dominant condition.

Autosomal dominant multiple epiphyseal dysplasia (MED) presents in early childhood, usually with pain in the hips and/or knees after exercise. Affected children complain of fatigue with long-distance walking. Waddling gait may be present. Adult height is either in the lower range of normal or mildly shortened. The limbs are relatively short in comparison to the trunk. Pain and joint deformity progress, resulting in early-onset osteoarthritis, particularly of the large weight-bearing joints.

Autosomal recessive form of spondyloepiphyseal dysplasia tarda.

Vitreoretinopathy with phalangeal epiphyseal dysplasia (VPED) is an autosomal dominant disorder characterized by rhegmatogenous retinal detachment, premature arthropathy, and development of phalangeal epiphyseal dysplasia, resulting in brachydactyly. Stature is normal, and high myopia, cleft palate, and midfacial hypoplasia are absent (Richards et al., 2002).

Spondyloarthropathy (SpA), one of the commonest chronic rheumatic diseases, includes a spectrum of related disorders comprising the prototype ankylosing spondylitis (AS), a subset of psoriatic arthritis (PsA), reactive arthritis (ReA), arthritis associated with inflammatory bowel disease, and undifferentiated spondyloarthropathy (Miceli-Richard et al., 2004). These phenotypes are difficult to differentiate because they may occur simultaneously or sequentially in the same patient. Studies have suggested that a predominant shared component, including HLA-B27, predisposes to all phenotypic subsets, and that these subsets should be considered as various phenotypic expressions of the same disease (Said-Nahal et al., 2000, Said-Nahal et al., 2001). Braun and Sieper (2007) provided a detailed review of ankylosing spondylitis, including clinical features, pathogenesis, and management. Genetic Heterogeneity of Susceptibility to Spondyloarthropathy Additional susceptibility loci for spondyloarthropathy have been identified on chromosome 9q31-q34 (SPDA2; 183840) and chromosome 2q36 (SPDA3; 613238).

Loeys-Dietz syndrome (LDS) is characterized by vascular findings (cerebral, thoracic, and abdominal arterial aneurysms and/or dissections), skeletal manifestations (pectus excavatum or pectus carinatum, scoliosis, joint laxity, arachnodactyly, talipes equinovarus, cervical spine malformation and/or instability), craniofacial features (widely spaced eyes, strabismus, bifid uvula / cleft palate, and craniosynostosis that can involve any sutures), and cutaneous findings (velvety and translucent skin, easy bruising, and dystrophic scars). Individuals with LDS are predisposed to widespread and aggressive arterial aneurysms and pregnancy-related complications including uterine rupture and death. Individuals with LDS can show a strong predisposition for allergic/inflammatory disease including asthma, eczema, and reactions to food or environmental allergens. There is also an increased incidence of gastrointestinal inflammation including eosinophilic esophagitis and gastritis or inflammatory bowel disease. Wide variation in the distribution and severity of clinical features can be seen in individuals with LDS, even among affected individuals within a family who have the same pathogenic variant.

The spectrum of CLCN7-related osteopetrosis includes infantile malignant CLCN7-related autosomal recessive osteopetrosis (ARO), intermediate autosomal osteopetrosis (IAO), and autosomal dominant osteopetrosis type II (ADOII; Albers-Schönberg disease). ARO. Onset is at birth. Findings may include: fractures; reduced growth; sclerosis of the skull base (with or without choanal stenosis or hydrocephalus) resulting in optic nerve compression, facial palsy, and hearing loss; absence of the bone marrow cavity resulting in severe anemia and thrombocytopenia; dental abnormalities, odontomas, and risk for mandibular osteomyelitis; and hypocalcemia with tetanic seizures and secondary hyperparathyroidism. Without treatment maximal life span in ARO is ten years. IAO. Onset is in childhood. Findings may include: fractures after minor trauma, characteristic skeletal radiographic changes found incidentally, mild anemia, and occasional visual impairment secondary to optic nerve compression. Life expectancy in IAO is usually normal. ADOII. Onset is usually late childhood or adolescence. Findings may include: fractures (in any long bone and/or the posterior arch of a vertebra), scoliosis, hip osteoarthritis, and osteomyelitis of the mandible or septic osteitis or osteoarthritis elsewhere. Cranial nerve compression is rare.

X-linked spondyloepiphyseal dysplasia tarda is a condition that impairs bone growth and occurs almost exclusively in males. The name of the condition indicates that it affects the bones of the spine (spondylo-) and the ends of long bones (epiphyses) in the arms and legs. "Tarda" indicates that signs and symptoms of this condition are not present at birth, but appear later in childhood, typically between ages 6 and 10.\n\nMales with X-linked spondyloepiphyseal dysplasia tarda have skeletal abnormalities and short stature. Affected boys grow steadily until late childhood, when their growth slows. Their adult height ranges from 4 feet 6 inches (137 cm) to 5 feet 4 inches (163 cm). Impaired growth of the spinal bones (vertebrae) primarily causes the short stature. Spinal abnormalities include flattened vertebrae (platyspondyly) with hump-shaped bulges, progressive thinning of the discs between vertebrae, and an abnormal curvature of the spine (scoliosis or kyphosis). These spinal problems also cause back pain in people with this condition. Individuals with X-linked spondyloepiphyseal dysplasia tarda have a short torso and neck, and their arms are disproportionately long compared to their height.\n\nOther skeletal features of X-linked spondyloepiphyseal dysplasia tarda include an abnormality of the hip joint that causes the upper leg bones to turn inward (coxa vara); multiple abnormalities of the epiphyses, including a short upper end of the thigh bone (femoral neck); and a broad, barrel-shaped chest. A painful joint condition called osteoarthritis that typically occurs in older adults often develops in early adulthood in people with X-linked spondyloepiphyseal dysplasia tarda and worsens over time, most often affecting the hips, knees, and shoulders.

Patients with short sature and advanced bone age with or without early-onset osteoarthritis and/or osteochondritis dissecans (SSOAOD) exhibit a broad phenotypic spectrum involving short stature associated with advanced bone maturation and early-onset osteoarthritis, as well as mild dysmorphic features consisting of midface hypoplasia, brachydactyly, broad great toes, and lumbar lordosis. Other features include intervertebral disc disease and osteochondritis dissecans, which is characterized by separation of articular cartilage and subchondral bone from the articular surface. Phenotypes are highly variable even among patients within the same family, and there are no apparent genotype-phenotype correlations (summary by Dateki et al., 2017). The term 'dissecans' comes from 'dis' meaning 'from' and 'secare' meaning 'cut off,' and is not to be confused with 'desiccans' derived from 'desiccare' meaning to 'dry up.' Dissecans refers to the appearance of part of the bone having been cut away.

Developmental dysplasia of the hip (DDH) is a debilitating condition characterized by incomplete formation of the acetabulum leading to dislocation of the femur, suboptimal joint function, and accelerated wear of the articular cartilage, resulting in arthritis. Undetected hip dysplasia is the leading cause of osteoarthritis of the hip in young individuals, causing over 40% of cases in that age group (summary by Feldman et al., 2013). For discussion of genetic heterogeneity of developmental dysplasia of the hip, see DDH1 (142700).

Osteoarthritis is a common disease of the joints that primarily occurs in older adults. This condition is characterized by the breakdown of cartilage, the tough but flexible tissue that covers the ends of the bones at the joints and allows smooth joint movements. One or more parts of the body can be affected, most often the hands, shoulders, spine, knees, or hips.\n\nOsteoarthritis usually develops slowly, causing pain, stiffness, and restricted movement as the condition gets worse. Areas of bone no longer cushioned by cartilage rub against each other and start to break down. Further damage is caused as the body attempts to repair and rebuild these tissues. The immune system, which plays a role in healing injuries, targets these areas, and its response leads to inflammation of the joint tissues. Abnormal growths of bone (osteophytes) and other tissue can also occur, and may be visible as enlarged joints. Enlargement of the joints of the fingers is especially noticeable.\n\nPeople with osteoarthritis typically experience stiffness following periods of inactivity such as upon awakening or rising from a chair; the stiffness usually improves as they move around. In some affected individuals, the condition never causes major problems. In others, severe osteoarthritis can impair mobility and the ability to perform daily tasks, affecting quality of life and increasing the risk of other health conditions such as cardiovascular disease.\n\nOsteoarthritis is most common in middle age or late adulthood, because the cartilage at the joints naturally begins to thin as people age. However, it can occur earlier in life, especially after injuries affecting the joints such as a type of knee injury called an anterior cruciate ligament (ACL) tear. People who are overweight or whose activities are particularly stressful to the joints are also at increased risk of developing osteoarthritis.

A rare primary bone dysplasia with characteristics of cone-shaped epiphyses of the phalanges, hyperextensibility and hyper-flexibility of the fingers and marked delay in ossification of hand bones. Short-limbed short stature, very stubby, short fingers and toes, flat face and nose and a large skull may also be associated. There have been no further descriptions in the literature since 1980.

Loeys-Dietz syndrome (LDS) is characterized by vascular findings (cerebral, thoracic, and abdominal arterial aneurysms and/or dissections), skeletal manifestations (pectus excavatum or pectus carinatum, scoliosis, joint laxity, arachnodactyly, talipes equinovarus, cervical spine malformation and/or instability), craniofacial features (widely spaced eyes, strabismus, bifid uvula / cleft palate, and craniosynostosis that can involve any sutures), and cutaneous findings (velvety and translucent skin, easy bruising, and dystrophic scars). Individuals with LDS are predisposed to widespread and aggressive arterial aneurysms and pregnancy-related complications including uterine rupture and death. Individuals with LDS can show a strong predisposition for allergic/inflammatory disease including asthma, eczema, and reactions to food or environmental allergens. There is also an increased incidence of gastrointestinal inflammation including eosinophilic esophagitis and gastritis or inflammatory bowel disease. Wide variation in the distribution and severity of clinical features can be seen in individuals with LDS, even among affected individuals within a family who have the same pathogenic variant.