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