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Dwarfism is
a congenital abnormality attributable to different causes (see the page
Principal
Causes of Dwarfism under Dwarfism). It is caused by different
bone diseases such as achondroplasia, osteogenesis imperfecta, and
Morquio syndrome (MPS IV), to name the most common types. There are
five-hundred known types of dwarfism in the world, 100 of which are
represented in Québec. The diseases that cause dwarfism lead to medical
complications such as functional
limitations and more or less severe handicaps. All types
of dwarfism are universally characterized by significant
underdevelopment leading to remarkably smaller than average height
(generally less then 1.42 m for adults).
There are
two kinds of dwarfism:
- Disproportionate:
these types of dwarfism (achondroplasia, pseudoachondroplasia, Morquio
syndrome, Léri-Weill dyschondrosteosis, etc.) affects long bones like
those of the arms and legs, but the trunk is unaffected.
-
Proportionate: caused by kidney failure, spondyloepiphyseal dysplasia,
intra-uterine dwarfism, hypopituitarism, etc., underdevelopment affects
the trunk and limbs equally. The body is proportionally small.
Dwarfism can
be hereditary (see the page Genetics),
but in most cases, dwarfism is caused by a simple genetic mutation (the
parents are not carriers and they are not little people, but a
spontaneous chromosome anomaly occurs at random). That being said,
anyone can have a child of small stature.
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