Achondroplasia

Dackelpferd The Achondroplasia (also Chondrodysplasia or Chondrodystrophia fetalis known) is one of many Mammals - Including humans - frequent MutationThat the growth of Skeletal system concerns. It is a smaller part autosomal--dominant inherited () about 20%, produced far greater part, however, by Mutation, Which increases the probability of occurrence especially with the age of the biological father. The shortened legs of some breeds, such as Dachshund and Basset Hound are the result of a targeted selection for achondroplasia, the Malformation is part of the Breed standards.

Frequency

One of 40,000 babies is born with achondroplasia.

Causes

Achondroplasia is the result of a Point mutation in Fibroblast growth factor receptor gene FGFR-3 These autosomal dominant Mutation leads to a disruption of Cartilage formationAnd the bone growth zone (Epiphyseal) Is premature ossification, leading to the reduction of longitudinal growth especially of the arms and legs (Extremities) Leads (Endochondral Ossification).

About 80% of cases by Mutations conditioned. The cause is present in 96% of cases, G (1138) A point mutation in the FGFR-3. It is here at position 380, the Amino Glycine through Arginine replaced. In 3% of the cases can be a G (show 1138) C point mutation at the Glycine through Glutamine is replaced. Embryo with homozygous Mutation (both the paternal and maternal variant of the gene are altered) are not viable and die in the womb (utero).

Common symptoms of mutation

The results in achondroplasia DISPROPORTIONATE Stature. As the unusual formation of cartilage, particularly in the Bones , proper development can not be possible, are greatly reduced Extremities characteristic. Linear growth is impaired by contrast, almost normal growth in thickness.

Other symptoms in people affected are:

  • relatively short fingers
  • increasing the distance between the 3rd and 4 Finger (Trident hand)
  • relatively short neck and large head with bulging forehead and unusual skull base
  • narrow face with Saddle nose
  • often hollow cross (Lordosis) Or a Kyphosis
  • congenital weakness of the entire spinal canal
  • often Bowlegged or X-Legs
  • frequent Otitis (due to constricted Eustachian tube)
  • characteristic skin folds (the skin is too much) for the shortened limbs
  • Hydrocephalus

Therapy

The therapy is based on the symptoms. For functional disability through the leg axis and spinal position as well as incipient paralysis decompression and stabilization procedures on the can Spine be made. Studies Growth hormone therapy (GH) Were performed, the results are still pending, because the people involved have not yet reached adulthood. Surgical leg lengthening with length win up to 20 cm is possible.

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