Platyspondylic lethal skeletal dysplasia Torrance type
Alternate names[edit | edit source]
PLSDT; Lethal short-limbed platyspondylic dwarfism Torrance type; Thanatophoric dysplasia torrance variant
Definition[edit | edit source]
Platyspondylic lethal skeletal dysplasia, Torrance type is a severe disorder of bone growth. People with this condition have very short arms and legs, underdeveloped pelvic bones, and unusually short fingers and toes (brachydactyly).
Epidemiology[edit | edit source]
This condition is very rare; only a few affected individuals have been reported worldwide.
Cause[edit | edit source]
- Platyspondylic lethal skeletal dysplasia, Torrance type 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 the clear gel that fills the eyeball (the vitreous) and in cartilage.
- Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development.
- Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears.
- Type II collagen is essential for the normal development of bones and other connective tissues that form the body's supportive framework.
Gene mutations[edit | edit source]
- All of the COL2A1 mutations that have been found to cause platyspondylic lethal skeletal dysplasia, Torrance type occur in a region of the protein called the C-propeptide domain.
- These mutations interfere with the assembly of type II collagen molecules, reducing the 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.
Inheritance[edit | edit source]
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.
Signs and symptoms[edit | edit source]
- This disorder is also characterized by flattened spinal bones (platyspondyly) and an exaggerated curvature of the lower back (lordosis).
- Infants with this condition are born with a small chest with short ribs that can restrict the growth and expansion of the lungs.
- As a result of these serious health problems, some affected fetuses do not survive to term.
- Infants born with platyspondylic lethal skeletal dysplasia, Torrance type usually die at birth or shortly thereafter from respiratory failure.
- A few affected people with milder signs and symptoms have lived into adulthood.
Clinical presentation[edit | edit source]
For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.
80%-99% of people have these symptoms
- Abdominal distention(Abdominal bloating)
- Abnormality of the carpal bones
- Disproportionate short-limb short stature(Short limb dwarfism, disproportionate)
- Hypoplasia of the capital femoral epiphysis(Small innermost thighbone end part)
- Hypoplastic pelvis
- Metaphyseal cupping
- Micromelia(Smaller or shorter than typical limbs)
- Narrow chest(Low chest circumference)
- Platyspondyly(Flattened vertebrae)
- Short distal phalanx of finger(Short outermost finger bone)
- Short foot(Short feet)
- Short palm
- Short thorax(Shorter than typical length between neck and abdomen)
- Skeletal dysplasia
30%-79% of people have these symptoms
- Depressed nasal bridge(Depressed bridge of nose)
- Genu varum(Outward bow-leggedness)
- Hydrops fetalis
- Hypoplastic scapulae(Small shoulder blade)
- Low-set ears(Low set ears)
- Malar flattening(Zygomatic flattening)
- Polyhydramnios(High levels of amniotic fluid)
- Prominent forehead(Pronounced forehead)
- Pulmonary hypoplasia(Small lung)
5%-29% of people have these symptoms
- Cleft palate(Cleft roof of mouth)
Diagnosis[edit | edit source]
Treatment[edit | edit source]
NIH genetic and rare disease info[edit source]
Platyspondylic lethal skeletal dysplasia Torrance type is a rare disease.
Platyspondylic lethal skeletal dysplasia Torrance type Resources | ||
---|---|---|
|
|
Translate to: East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
Urdu,
বাংলা,
తెలుగు,
தமிழ்,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
European
español,
Deutsch,
français,
русский,
português do Brasil,
Italian,
polski
Navigation: Wellness - Encyclopedia - Health topics - Disease Index - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro) available.
Advertise on WikiMD
WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Deepika vegiraju