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2005-03-02-11 Fibrochondrogenesis © Alvarez-Arrazola www.thefetus.net/

Fibrochondrogenesis  

Raúl A. Alvarez-Arrazola, MD

Residente radiologia diagnostica e imagen; Jefe de residentes; Hospital San Jose tec de Monterrey; Monterrey, NL. MX

Definition: Fibrochondrogenesis is one of the rare lethal osteochondrodysplasias, which show abnormal maturation, and disturbed growth of cartilage and bones.1,2 It is characterized by the following:

  • Lethal rhizomelic chondrodysplasia
  • Relative large skull with wide anterior fontanelle
  • Hypoplastic facial bones
  • Thin and long clavicles
  • Short and elevated scapulae
  • Flat vertebral bodies (AP view)
  • Pear-shaped vertebral bodies with sagittal clefting (Lateral view)
  • Ribs short, wide and cupped
  • Short broad iliac bones, sciatic notch and caudally bump-like configuration (bordered by spurs)
  • Short and broad long bones (dumb-bell shaped) with irregular metaphases and peripheral spurs
  • Ectopic extra-articular calcification
  • Mild brachydactyly with relatively normal hands and feet

History: This neonatal lethal chondrodysplasia with histological characteristics was first described in 1978 by Lazzaroni-Fossati et al. 2,3

Prevalence: Only 13 cases have been reported. These disorders are a heterogeneous group of genetic disorders with a total incidence of 1-3 in 10,000 births.4

Etiology: Transmission is probably autosomal recessive.1-3

Pathogenesis: The chondro-osteal histopathology is diagnostic. Gross disorganization of the growth plate cartilage and fibrous appearance of the matrix. Interwoven fibrous septa and fibroelastic degeneration of chondrocytes are pathognomonic. 2,4

Sonographic findings:

  • Protuberant eyes,
  • Flat midface,
  • Flat small nose with anteverted nares,
  • Small mouth with long upper lip,
  • Cleft palate,
  • Micrognathia,
  • Bifid tongue,
  • Marked shortnening of all segments of the limbs with relatively normal hands and feet.

Implications for targeted examinations:
Look for short and broad (dumb-Bell Shaped) long bones and marked shortness of all the segments of the limbs with relatively normal hands and feet.

Differential diagnosis: Disorders manifested by osteochondrodysplasias with micromelia such as thanatophoric dysplasia, achondrogenesis, diastrophic dysplasia.

Associated anomalies: No anomalies other than omphalocele has been reported. 2

Prognosis: This condition is a neonatally lethal rhizomelic chondrodysplasia. 1-3

Recurrence risk: Recurrence rate is 25%. Recurrences in a consanguineous family affecting both sexes and concordance of affected male twins have been reported. 5,6

Management: In cases of prenatal diagnosis of fetal dwarfism, the problem is to make an accurate diagnosis of the disease using careful ultrasonographic and radiological examination. But in many instances, only a differential diagnosis can be given prenatally and prognosis is often limited to the distinction between a lethal or non-lethal type of dysplasia. Once a non-lethal type of dysplasia has been diagnosed, the degree of growth impairment needs to be assessed.7 Early ultrasound diagnosis allows pregnancy termination if opted by the parents, but a precise prenatal diagnosis of this lethal condition may be difficult.

References: 
1. Al Gazali LI, Bakalinova D, Bakir M, Dawodu A. Fibrochondrogenesis: clinical and radiological features. CLin Dysmorphol 1997;6:157-163.
2. Al Gazali, LI. Fibrochondrogenesis. Orphanet encyclopedia, March 2003.
http://www.orpha.net/data/patho/GB/uk-fibrochon.pdf 
3. Martinez-Frias ML, Garcia A, Cuevas J, Rodriguez JI, Urioste M.  A new case of fibrochondrogenesis from Spain. J Med Genet 1996;33:429-431.
4. Leeners B, Funk A, Cotarelo CL, Sauer L. Two sibs with fibrochondrogenesis. Am J Med Genet. 2004 Jun 15;127A(3):318-20.
5. Randrianaivo H, Haddad G, Roman H, Delezoide AL, Toutain A, Le Merrer M, Moraine C.  Fetal fibrochondrogenesis at 26 weeks of gestation. Prenat Diagn. 2002 Sep;22(9):806-810.
6. Al Gazali LI, Bakir M, Dawudo A, Haas D. Recurrence of fibrochondrogenesis in a consaguineous family. Clin Dysmorphol 1999;20:59-62.
7. Whitley CB, Langer LO Jr, Ohoven J, et al. Fibrochondrogenesis: lethal, autosomal recessive chondrodysplasia with distinctive cartilage histopathology. Am J Med Genet 1984;19:265-275

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