Atelosteogenesis type I

Atelosteogenesis type I is a rare autosomal dominant condition. This condition is evident at birth and is associated with a very poor prognosis for the baby. It may be diagnosed antenatally.

Signs and symptoms
Clinical features include


 * Abnormal facies
 * Prominent forehead
 * Hypertelorism
 * Depressed nasal bridge with a grooved tip
 * Micrognathia
 * Cleft palate
 * Severe short limbed dwarfism
 * Joint dislocations (hip, knee and elbow joints)
 * Club feet
 * Cardiorespiratory failure

Cardiorespiratory failure is due to pulmonary hypoplasia or tracheobronchial hypoplasia.

Genetics
This condition is caused by mutations in the filamin B (FLNB) gene. This gene is located on the short arm of chromosome 3 (3p14).

Pathogenesis
Filamin B forms part of the actin cytoskeleton. How these mutations produce the clinical picture is not yet clear.

Diagnosis
This condition is evident at birth and may be diagnosed antenatally with ultrasound or magnetic resonance imaging. The infants may be still born. Those that are live born do not survive long.

Radiological findings include


 * Severe platyspondyly
 * Distally tapered, shortened, incomplete or absent humeri and femurs
 * Shortened or bowed radii, ulnas and tibias
 * Hypoplastic pelvis and fibulas
 * Deficient ossification of the metacarpals, middle and proximal phalanges

Differential diagnosis
This includes


 * Achondroplasia
 * Achondrogenesis
 * Atelosteogenesis III
 * Boomerang dysplasia
 * Campomelic dysplasia
 * Ellis–Van Creveld syndrome
 * Hypophosphatasia
 * Melnick Needles syndrome
 * Metatropic dysplasia
 * Osteogenesis imperfecta
 * Roberts syndrome
 * Short-rib polydactyly syndrome
 * Thanatophoric dysplasia

Treatment
There is currently no curative treatment for this condition. Supportive management is all that is currently available.

Epidemiology
This is a rare condition with a prevalence of less than 1/106. The total number of cases reported to date is less than 20.

History
This condition was first described by Maroteaux et al. in 1982.