Thanatophoric Dysplasia, Type I

Alternative Names

  • TD
  • TD1
  • Lethal Short-Limbed Platyspondylic Dwarfism, San Diego Type
  • Platyspondylic Lethal Skeletal Dysplasia, San Diego Type
  • Thanatophoric Dwarfism
  • Thanatophoric Dysplasia
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WHO-ICD-10 version:2010

Congenital malformations, deformations and chromosomal abnormalities

Congenital malformations and deformations of the musculoskeletal system

OMIM Number


Mode of Inheritance

Autosomal dominant

Gene Map Locus



Thanatophoric dysplasia is the most frequent form of lethal osteochondrodysplasias with an estimated frequency of nearly of 1 in 20,000 births. Thanatophoric dysplasia is classified into two types: TD type 1 patients have curved femurs with or without a cloverleaf skull, and in the second type patients always have straight femurs and a cloverleaf skull. Affected individuals usually die within minutes or days after birth.

Thanatophoric dysplasia is an autosomal dominant disorder. Prenatal diagnosis is commonly accomplished in the second-trimester scan, but occasionally thanatophoric dysplasia may not be clearly distinguished from the other osteochondrodysplasias, with consequent important prognostic implications. However, in order to confirm the diagnosis, complementary radiological, pathological and molecular studies are mandatory.

Thanatophoric dysplasia type I is associated with mutations in the transmembrane domains of the fibroblast growth factor receptor 3 (FGFR3) gene, located on the short arm of chromosome 4 (4p16.3).

Epidemiology in the Arab World

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Subject IDCountrySexFamily HistoryParental ConsanguinityHPO TermsVariantZygosityMode of InheritanceReferenceRemarks
187600.1United Arab EmiratesUnknown Thanatophoric dysplasia... NM_000142.4:c.742C>THeterozygousAutosomal, DominantSimsek et al. 2003
187600.2United Arab EmiratesUnknownNoNo Death in infancy; Short long bone; Fe... NM_000142.4:c.742C>THomozygousAutosomal, DominantBekdache et al. 2010
187600.3Saudi ArabiaFemaleYesNo Skeletal dysplasia; Depressed nasal brid... NM_000142.4:c.742C>THeterozygousAutosomal, DominantMaddirevula et al. 2018 De novo mutation

Other Reports


Chemke et al. (1971) and Graff et al. (1972) described thanatophoric dwarfism in two male offspring of first-cousin Moroccan Jewish parents. However, after review of the radiographs of one, Rimoin (1975) concluded that this was not thanatophoric dwarfism. Knowles et al. (1986) and Borochowitz et al. (1986) suggested that the disorder reported by Chemke et al. (1971) and Graff et al. (1972) was the same as the 'new' autosomal recessive dysplasia they described under the designation of Schneckenbecken dysplasia.


Sawardekar (2005) conducted a study to establish the prevalence of major congenital malformations in children born during a 10-year period in Nizwa Hospital. Of the 21,988 total births in the hospital, seven children were born with Thanatophoric Dysplasia. Sawardekar (2005) hinted for a possible genetic contribution in these children.

United Arab Emirates

Al Talabani et al. (1998) studied the pattern of major congenital malformations in births between 1992 and 1995 and observed one case of thanatophoric dysplasia in a family from the United Arab Emirates. 

Al-Gazali et al. (2003) defined the pattern and birth prevalence of Thanatophoric dysplasia in the United Arab Emirates to be 0.78/10,000 births (0.09-0.60/10,000 worldwide) and the mutation rate to be 0.39/10,000. 

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