Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans (GAGs). These long chains of sugar carbohydrates occur within the cells that help build bone, cartilage, tendons, corneas, skin and connective tissue. GAGs are also found in the fluids that lubricate joints.
Diastrophic dysplasia is an autosomal recessive dysplasia which affects cartilage and bone development. Diastrophic dysplasia is due to mutations in the SLC26A2 gene.
Atelosteogenesis, type II is a severe disorder of cartilage and bone development. It is rare, and infants with the disorder are usually stillborn; those who survive birth die soon after.
Achondrogenesis is a number of disorders that are the most severe form of congenital chondrodysplasia. These conditions are characterized by a small body, short limbs, and other skeletal abnormalities. As a result of their serious health problems, infants with achondrogenesis are usually born prematurely, are stillborn, or die shortly after birth from respiratory failure. Some infants, however, have lived for a while with intensive medical support.
Spondyloperipheral dysplasia is an autosomal dominant disorder of bone growth. The condition is characterized by flattened bones of the spine (platyspondyly) and unusually short fingers and toes (brachydactyly). Some affected individuals also have other skeletal abnormalities, short stature, nearsightedness (myopia), hearing loss, and mental retardation. Spondyloperipheral dysplasia is a subtype of collagenopathy, types II and XI.
Hypochondrogenesis is a severe genetic disorder causing malformations of bone growth. The condition is characterized by a short body and limbs and abnormal bone formation in the spine and pelvis.
Achondrogenesis, type 2 is an uncommon skeletal dysplasia that is autosomal dominant and occurs at a frequency of approximately 0.2 per 100,000 births. Also known by the name Langer-Saldino achondrogenesis, it is one of the fatal short-limbed dwarfisms linked to structural mutations in type II collagen.
Otospondylomegaepiphyseal dysplasia (OSMED) is an autosomal recessive disorder of bone growth that results in skeletal abnormalities, severe hearing loss, and distinctive facial features. The name of the condition indicates that it affects hearing (oto-) and the bones of the spine (spondylo-), and enlarges the ends of bones (megaepiphyses).
Collagen, type II, alpha 1 , also known as COL2A1, is a human gene that provides instructions for the production of the pro-alpha1(II) chain of type II collagen.
Platyspondylic lethal skeletal dysplasia, Torrance type is a severe disorder of bone growth. People with this condition have very short arms and legs, a small chest with short ribs, underdeveloped pelvic bones, and unusually short fingers and toes (brachydactyly). This disorder is also characterized by flattened spinal bones (platyspondyly) and abnormal curvature of the spine (lordosis).
Autosomal recessive multiple epiphyseal dysplasia (ARMED), also called epiphyseal dysplasia, multiple, 4 (EDM4), multiple epiphyseal dysplasia with clubfoot or –with bilayered patellae, is an autosomal recessive congenital disorder affecting cartilage and bone development. The disorder has relatively mild signs and symptoms, including joint pain, scoliosis, and malformations of the hands, feet, and knees.
SCARF syndrome is a rare syndrome characterized by skeletal abnormalities, cutis laxa, craniostenosis, ambiguous genitalia, psychomotor retardation, and facial abnormalities. These characteristics are what make up the acronym SCARF. It shares some features with Lenz-Majewski hyperostotic dwarfism. It is a very rare disease with an incidence rate of approximately one in a million newborns. It has been clinically described in two males who were maternal cousins, as well as a 3-month-old female. Babies affected by this syndrome tend to have very loose skin, giving them an elderly facial appearance. Possible complications include dyspnea, abdominal hernia, heart disorders, joint disorders, and dislocations of multiple joints. It is believed that this disease's inheritance is X-linked recessive.
An osteochondrodysplasia, or skeletal dysplasia, is a disorder of the development of bone and cartilage. Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia. Nonetheless, if taken collectively, genetic skeletal dysplasias or osteochondrodysplasias comprise a recognizable group of genetically determined disorders with generalized skeletal affection. These disorders lead to disproportionate short stature and bone abnormalities, particularly in the arms, legs, and spine. Skeletal dysplasia can result in marked functional limitation and even mortality.
Maroteaux–Lamy syndrome, or Mucopolysaccharidosis Type VI (MPS-VI), is an inherited disease caused by a deficiency in the enzyme arylsulfatase B (ARSB). ASRB is responsible for the breakdown of large sugar molecules called glycosaminoglycans. In particular, ARSB breaks down dermatan sulfate and chondroitin sulfate. Because people with MPS-VI lack the ability to break down these GAGs, these chemicals build up in the lysosomes of cells. MPS-VI is therefore a type of lysosomal storage disease.
Multiple epiphyseal dysplasia (MED), also known as Fairbank's disease, is a rare genetic disorder that affects the growing ends of bones. Long bones normally elongate by expansion of cartilage in the growth plate near their ends. As it expands outward from the growth plate, the cartilage mineralizes and hardens to become bone (ossification). In MED, this process is defective.
The sulfate transporter is a solute carrier family protein that in humans is encoded by the SLC26A2 gene. SLC26A2 is also called the diastrophic dysplasia sulfate transporter (DTDST), and was first described by Hästbacka et al. in 1994. A defect in sulfate activation described by Superti-Furga in achondrogenesis type 1B was subsequently also found to be caused by genetic variants in the sulfate transporter gene. This sulfate (SO42−) transporter also accepts chloride, hydroxyl ions (OH−), and oxalate as substrates. SLC26A2 is expressed at high levels in developing and mature cartilage, as well as being expressed in lung, placenta, colon, kidney, pancreas and testis.
Keutel syndrome (KS) is a rare autosomal recessive genetic disorder characterized by abnormal diffuse cartilage calcification, hypoplasia of the mid-face, peripheral pulmonary stenosis, hearing loss, short distal phalanges (tips) of the fingers and mild mental retardation. Individuals with KS often present with peripheral pulmonary stenosis, brachytelephalangism, sloping forehead, midface hypoplasia, and receding chin. It is associated with abnormalities in the gene coding for matrix gla protein, MGP. Being an autosomal recessive disorder, it may be inherited from two unaffected, abnormal MGP-carrying parents. Thus, people who inherit two affected MGP alleles will likely inherit KS.
Boomerang dysplasia is a lethal form of osteochondrodysplasia known for a characteristic congenital feature in which bones of the arms and legs are malformed into the shape of a boomerang. Death usually occurs in early infancy due to complications arising from overwhelming systemic bone malformations.
Desmin-related myofibrillar myopathy, is a subgroup of the myofibrillar myopathy diseases and is the result of a mutation in the gene that codes for desmin which prevents it from forming protein filaments, instead forming aggregates of desmin and other proteins throughout the cell.
Progressive pseudorheumatoid disyplasia, also known as progressive pseudorheumatoid arthropathy of childhood (PPAD), is a disorder of bone and cartilage that affects many joints. The disorder leads to stiff joints, short stature and widening of the ends of the finger and toe bones as well as other tubular bones.
