Primordial dwarfism
From Wikipedia, the free encyclopedia
Primordial dwarfism is a form of dwarfism that results in a smaller body size in all stages of life beginning from before birth. It is the most severe form of dwarfism.
Contents |
[edit] Medical definition
Primordial dwarfism (PD) is a diagnostic category including various specific types of severe proportionate dwarfism in which individuals are small for their chronological age from the very beginning of their life.
[edit] History
Caroline Crachami was the first recognized individual with primordial dwarfism. She was born in Palermo, Italy in 1815. The exact history is unclear, but a 'Dr. Gilligan,' an Irishman pretending to be her father, exhibited her in London. Various descriptions arose from these exhibitions. It was said that she walked on her own, but without 'confidence.' She was reported to know enough English to express herself fluently. Her voice was said to be thin and high pitched. Due to this, Dr. Gilligan had to repeat much of what she said to the audience.
Shortly before her death in 1824, a journalist named William Jerdan was able to obtain her measurements for print. Her height was 19½ inches (49.5 cm), the length of her foot, 3 inches (7.6 cm) and the length of her forefinger, 1 7/8 inches (4,7 cm). Her head circumference was measured at 12 3/8 inches (31.4 cm) and her waist circumference, 11¼ inches (28.5 cm). He wrote:
- "Only imagine a creature about half as large as a new-born infant; perfect in all its parts and lineaments, uttering words in a strange, unearthly voice, understanding what you say and replying to your questions. Imagine I say, this figure of about 19 ½ inches in height and 5 pounds (2.3 kg) in weight, and you will have some idea of this most extraordinary phenomenon."
During the first half of the 20th century, several new cases of dwarfism were published and their similarity to Caroline Crachami was noted. In 1960, Professor H.P.G. Seckel described a new syndrome, which is now referred to as Seckel syndrome. Since then, new cases of Seckel syndrome, in addition to other comparable types of severe dwarfism, have been published in the literature. These various reports illustrate both striking similarities as well as differences in these individuals. These include the osteodysplastic types of primordial dwarfism as described by Majewsky, as well as others.
The ambiguity surrounding these conditions has led to the creation of the umbrella diagnosis of primordial dwarfism (PD), essentially meaning small from the very beginnings of life. Therefore, since the initial description of Seckel syndrome in 1960, there has been perplexity and debate in the professional community about the delineation (definition/separation) of the specific syndromes within this category.
[edit] Diagnosis
Individuals with primordial dwarfism usually come to medical attention even before they are born. Most are diagnosed by ultrasound as small for gestational age (SGA) or as having intrauterine growth retardation (IUGR). Consequently, they are born at extremely low birth weights (less than 4 pounds). However, even though infants with PD are small, they are not necessarily recognized as having dwarfism because they are proportionately small.
Since primordial dwarfism disorders are extremely rare, misdiagnosis is common. After birth, growth occurs at an extremely slow rate leaving affected individuals years behind their peers in size. Individuals with primordial dwarfism measure well below the 3rd percentile on standardized growth charts. Because children with PD do not grow like other children, poor nutrition, a metabolic disorder, or a digestive disorder may be diagnosed initially. The correct diagnosis of PD may not be made until time has passed and it becomes apparent that the child has severe dwarfism.
[edit] Treatment
What causes primordial dwarfism is not yet known, and there are as yet no effective treatments for the disorder. The lack of normal growth in the disorder is not due to a deficiency of growth hormone, as in hypopituitary dwarfism. Administering growth hormone, therefore, has little or no effect on the growth of the individual with PD.
[edit] Types
There are five conditions included within the category of primordial dwarfism:
- Seckel syndrome
- Majewski osteodysplastic primordial dwarfism (MOPD) types I/III
- Majewski osteodysplastic primordial dwarfism (MOPD) type II
- Meier-Gorlin Syndrome
- Russell-Silver syndrome
The number of possible syndromes being included within this category is constantly changing due to a combination of advances in research and the complexity surrounding many of these conditions.
Within some of the types of primordial dwarfism, there has been considerable debate and significant confusion over which clinical findings constitute a particular syndrome. In general, each type of dwarfism is defined by its own physical, mental and developmental findings. In the many forms of primordial dwarfism, these are not so clearly defined and separated. In addition to the severity of growth delay itself, many of the health findings vary widely. Many affected individuals are generally referred to as having of primordial dwarfism because specific diagnosis within the category of primordial dwarfism is difficult.
[edit] Current research
Seckel and Russell-Silver syndromes are the most clearly defined syndromes within the category of primordial dwarfism. Progress on these two syndromes has taken a path of its own and Russell-Silver syndrome in particular is not generally included in the debate on delineation (separation/definition). Meier-Gorlin, when accurately diagnosed, is also associated with a unique physical appearance, although medical and health expectations are still vague. These three conditions have particular physical characteristics such that a knowledgeable geneticist is now able to distinguish these syndromes from others. Unfortunately, however, the extreme rarity of these conditions often leads to misdiagnosis. Accurate diagnosis is more difficult with the osteodysplastic types of primordial dwarfism, even with the most experienced geneticists.
While still quite rare, in contrast to the few scattered case reports found throughout history, publications on primordial dwarfism have emerged at an increasing rate. More children are being diagnosed with primordial dwarfism, perhaps due to overall increased awareness in combination with recent advances in neonatal care. In response to the increasing number of children being identified with primordial dwarfism, the interest in this condition has grown, along with the desire to more accurately define each of the syndromes within this category.
