Platyspondylic lethal skeletal dysplasia, Torrance type

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).

As a result of these serious skeletal problems, many infants with platyspondylic lethal skeletal dysplasia, Torrance type are born prematurely, are stillborn, or die shortly after birth from respiratory failure. A few affected people with milder signs and symptoms have lived into adulthood, however.

This condition is one of a spectrum of skeletal disorders caused by mutations in the COL2A1 gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). It is essential for the normal development of bones and other tissues that form the body's supportive framework (connective tissues).

Mutations in the COL2A1 gene interfere with the assembly of type II collagen molecules, resulting in a reduced amount of this type of collagen in the body. Instead of forming collagen molecules, the abnormal COL2A1 protein builds up in cartilage cells (chondrocytes). These changes disrupt the normal development of bones and other connective tissues, leading to the skeletal abnormalities characteristic of platyspondylic lethal skeletal dysplasia, Torrance type.

Platyspondylic lethal skeletal dysplasia, Torrance type is inherited in an autosomal dominant pattern.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

General reference

This article incorporates public domain text from The U.S. National Library of Medicine

Diseases of collagen, laminin and other scleroproteins

Collagen disease

COL1:	Osteogenesis imperfecta Ehlers–Danlos syndrome, types 1, 2, 7

COL2:	Hypochondrogenesis Achondrogenesis type 2 Stickler syndrome Marshall syndrome Spondyloepiphyseal dysplasia congenita Spondyloepimetaphyseal dysplasia, Strudwick type Kniest dysplasia (see also C2/11)

COL3:	Ehlers–Danlos syndrome, types 3 & 4 Sack–Barabas syndrome

COL4:	Alport syndrome

COL5:	Ehlers–Danlos syndrome, types 1 & 2

COL6:	Bethlem myopathy Ullrich congenital muscular dystrophy

COL7:	Epidermolysis bullosa dystrophica Recessive dystrophic epidermolysis bullosa Bart syndrome Transient bullous dermolysis of the newborn

COL8:	Fuchs' dystrophy 1

COL9:	Multiple epiphyseal dysplasia 2, 3, 6

COL10:	Schmid metaphyseal chondrodysplasia

COL11:	Weissenbacher–Zweymüller syndrome Otospondylomegaepiphyseal dysplasia (see also C2/11)

COL17:	Bullous pemphigoid

Laminin

Other

see also fibrous proteins

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