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The estimated incidence is around 1:25,000-50,000 3.
There are two recognized subtypes:
marked underdevelopment of the skeleton
telephone handle femurs are more pronounced
the presence of a cloverleaf skull may be a distinctive feature
limb shortening milder and bowing is not a feature 3
It results from a mutation coding for the fibroblast growth receptor 3 (FGFR3) located on chromosome 4p16.3. The type of receptor mutation is different from the FGFR mutation in achondroplasia. Inheritance is thought to be sporadic.
Plain films are usually done postmortem, if done at all. Features include:
proximal portions of the long limbs are small, giving a rhizomelic appearance
long bones (typically humeri and femora) have a typical "telephone handle" bowing with metaphyseal flaring
short horizontal ribs
Skull and face
nasal bridge flattening
kleeblattschaedel (cloverleaf) skull (with type II) 2-4
platyspondyly: flattening of vertebral bodies
normal trunk length
It may be difficult to accurately diagnose before the 3rd trimester (~22 weeks) 4. Before that time it can be included in the differential if there is a short femur length measurement.
Sonographically-detectable features may include:
relatively narrow thoracic cavity 4
short, thick, bowed tubular bones, especially of lower extremities 4
thickened soft tissues of extremities 4
comparatively large head with frontal bossing
a cloverleaf skull appearance may also be seen: type II (see case 3)
Treatment and prognosis
The condition is uniformly fatal within a few hours of birth either from respiratory failure or from brainstem compression from a narrow foramen magnum.
History and etymology
The term thanatophoric derives from the Greek words "thanatos" (θάνατος) meaning "death" 2 and "phoros" meaning "bearing/carrying/bringing".
- 1. Dähnert WF. Radiology Review Manual. Lippincott Williams & Wilkins. (2011) ISBN:1609139437. Read it at Google Books - Find it at Amazon
- 2. Dighe M, Fligner C, Cheng E et-al. Fetal skeletal dysplasia: an approach to diagnosis with illustrative cases. Radiographics. 28 (4): 1061-77. doi:10.1148/rg.284075122 - Pubmed citation
- 3. Miller E, Blaser S, Shannon P et-al. Brain and bone abnormalities of thanatophoric dwarfism. AJR Am J Roentgenol. 2009;192 (1): 48-51. doi:10.2214/AJR.08.1524 - Pubmed citation
- 4. Burrows PE, Stannard MW, Pearrow J et-al. Early antenatal sonographic recognition of thanatophoric dysplasia with cloverleaf skull deformity. AJR Am J Roentgenol. 1984;143 (4): 841-3. AJR Am J Roentgenol (citation) - Pubmed citation
- 5. Fink AM, Hingston T, Sampson A et-al. Malformation of the fetal brain in thanatophoric dysplasia: US and MRI findings. Pediatr Radiol. 2010;40 Suppl 1 : S134-7. doi:10.1007/s00247-010-1697-4 - Pubmed citation
- 6. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon