Achondroplasia like Down syndrome were once disorders included in the large heterogeneous categories of "Dwarfisms" and "Cretinisms". Clinical "Semiologists" (students of signs) did recognize both disorders as distinct "sub-types". Among the dysmorphic sings (disproportions and malformations), those of the face were quite charactersitic. In fact, the "facies" (facial peculiarities) can trigger the diagnosis by Clinical Dysmorphologists and benefit the patient by accelerating the formal diagnosis and early specific health care interventions.
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Individuals with achondroplasia have a typical best appreciated visually than grasped from words. |
The artistic genius of Velazquez is evident in the illustrated paintings where he shows the charateristic "dysmorphic" signs (disorted shapes and proportions) characteristic of achondroplasia, namely a saddle like nose, prominent forehead, short limbs, among other signs. The fact that persons with achodroplasia served royalty by holding important posts illustrates that, in general, the disorder does not impact brain development.
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In general, the achondroplasia "facies" includes a prominent forehead, a flat nasal bridge (pub like nose) and at times, a prominent jaw or prognatism. |
Extract from a Classic Description
(Josef Warkany, in Congenital Malformations, Year Book Publishers, 1971.)
"... A limestone statuette of Chnoum-hotep from about 2700 BC shows a man with a large head, diminutive lower limbs, short digits and upper limbs, lordosis and good muscular development. This individual had normal intelligence because he was "chief of the Perfumes" or "Head of the Wardrobe. Other achodroplastic dwarfs in Egypt were in charge of pets or jewelry ... Good mental development and provocative wit in a person with somewhat grotesque physical features made these dwarfs valuable adjuncts of a princely household ... the demands for achodroplastics was at times greater than the supply, so that increased production was attempted ... done by dwarf marriages ... by deficient diets imposed on children ... it became customary to have paintings made of successful court dwarfs ...
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Peter "the Great" of Moscovy and founder of the "Empire of All Russians" was a great imitator and had a propensity toward excesses - he "encouraged" marriages amongst dwarfs - the high prenatal mortality of dwarfed mothers and their newborns later led to the banning of such marriages. |
... The best description of an achondroplastic dwarf was given - before Parrot - in David Copperfield by Dickens, who described Miss Mowcher ...
Achondroplasia or chondrodystrophy is known to occur in animals in many forms. It can affect the entire skeleton or only parts of it ...Tux-Zillertal cattle ... Peking-ese and French bulldog are examples of generalized chondrodystrophy, whereas in Niata cattle and Yorkshire swine the anomaly is limited to the head ... dachshund ... the extremities are shortened and the head and spine are normal ...
... Porak described the first hereditary instance (of achondroplasia) ... (a review) prior to 1912 (of 80 pedigrees showed that) 55 were solitary cases and 25 (pedigrees had) more than one case ... in 14 (pedigrees there were) two or more generations (were affected) ... Morch concluded that in the familial cases the disorder was transmitted as a dominant character ... the sporadic or spontaneous cases were due to mutation; they were potential initiators of families in which about 50% of the offspring would have been affected ... the possibility of recessive inheritance was denied by Morch ... Concordance has been observed in identical twins and discordance in nonidentical twins ...
The results of matings of two achondroplasts are of great interest ... the pregnancies ... are terminated prematurely ... (the fetus who inherits the achodroplasia gene from both parents ["double hit"] manifests a more severe and lethal skeletal dysplasia named "achondrogenesis", the matter is further complicated since the same mutated gene can cause diverse phenomena or phenotypes, in short, "achondroplasia type of chondrodystrophy is for the time being, the most precise label for this sort of disorder) ... Advanced parental age (paternal in particular) has been known to be an etiologic factor in achondroplasia since 1912 ... Penrose found and Murdoch confirmed that paternal age is the major factor in the origin of new mutations of achodroplasia. ... if the mother is dwarfed, the birth weights are lower ...In the newborn, the head is of normal size but there are frontal and parietal eminences and the root of the nose is depressed.
The bones of the skull are of normal hardness and the fontanelles and sutures of normal width, ... The trunk is of almost normal size but the ribs are flaring and a rosary can be felt at the costochondral junction ... The limbs are short, thick and curved ... In some patients the skin appears too large for the size of the bones ... "like an accordion" ...
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A person with typical features of Achondroplasia. |
Achodroplastic dwarfs often can be recognized at a glance by their short extremities, which are attached to a relatively large trunk, and by the large head and typical facial features. The forehead is high and bulging. The root of the nose is broad and depressed and the features are coarse. The mandible is disproportionately large and the chin protruding. The palate is high and malposition of teeth frequently is present. The chest, although of nearly normal length, is contracted in the anteroposterior diameter. A ridge formed by prominent costochondral junctions may be visible. The abdomen is prominent. An exaggerated lumbar lordosis and prominence of the buttocks are characteristic ...
In addition ... lumbar lordosis (is common) ... scoliosis is rare ... the height of the vertebral bodies appears reduced and the intervertebral spaces enlarged ... lumbar bodies taper in width and with this goes a narrowing of the lumbar spinal canal ... may lead to neurologic complications ... spinal cord and cauda equina ... can be compressed easily ... Pelvic changes are of great biologic importance, ... inability of female achodroplastics to deliver without expert help ...
With the arms hanging at the sides, the fingertips usually do not reach below the major trochanter of the femur. The shortening is more marked in the proximal than in the distal tubular bones (rhizomelia). The wrists and ankles often are prominent owing to terminal spread of the bones ... The hands and feet are short and broad. Sometimes there is a divergence of the third and fourth fingers whereby a "trident" hand is formed. Coxa vara frequently is present and the feet are turned inward, which explains the waddling gait so characteristic of achondroplasia ... Although achondroplastic dwarfs usually can be recognized at a glance, they do not represent as uniform a disease picture as is generally assumed ...
The mental and artistic faculties ... should be developed. Today, there exist many more specialties in which the brain rather than the length of the extremities counts." ...
(note other overviews on the subject)
(clinical and parental support information is found in achondroplasia )
W. Wertelecki, M.D.
20091114n
