Microcephalic primordial dwarfism
Overview
Primordial dwarfism is a rare form of dwarfism that results in a smaller body size in all stages of life beginning from before birth. More specifically, primordial dwarfism is a diagnostic category including specific types of profoundly proportionate dwarfism, in which individuals are extremely small for their age, even as a fetus. Most individuals with primordial dwarfism are not diagnosed until they are about 3 years of age. Medical professionals typically diagnose the fetus as being small for the gestational age, or as having intrauterine growth retardation when an ultrasound is conducted. Typically, people with primoridal dwarfism are born with very low birth weights. After birth, growth continues at a stunted rate, leaving individuals with primordial dwarfism perpetually years behind their peers in stature and in weight. Most cases of short stature are caused by skeletal or endocrine disorders. The five subtypes of primordial dwarfism are the most severe forms of the 200 types of dwarfism, and it is estimated that there are only 100 individuals in the world with the disorder. Other sources list the number of persons currently afflicted as high as 100 in North America.[citation needed] It is rare for individuals affected by primordial dwarfism to live past the age of 30. In the case of microcephalic osteodysplastic primordial dwarfism (MOPD) type II there can be increased risk of vascular problems, which may cause premature death.
Symptoms
The list of signs and symptoms mentioned in various sources for Microcephalic primordial dwarfism, Toriello type includes the 18 symptoms listed below: * Retarded fetal growth * Dwarfism * Small head * Mental retardation * Cataract * Underdeveloped thin enamel * Immune deficiency * Delayed calcification of bones * Short fingers * Chronic inflammatory lung disease * Downslanted space between eyelids * Short foot * Abnormal rib number * Reduced muscle tone * Downturned mouth * Small face * Neutropenia * Dilated cerebral ventricles Note that Microcephalic primordial dwarfism, Toriello type symptoms usually refers to various symptoms known to a patient, but the phrase Microcephalic primordial dwarfism, Toriello type signs may refer to those signs only noticable by a doctor.
Causes
It is known that PD is caused by inheriting a mutant gene from each parent. 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 Primordial Dwarfism. In January 2008, it was published that mutations in the pericentrin gene (PCNT) were found to cause primordial dwarfism. Pericentrin has a role in cell division, proper chromosome segregation, and cytokinesis suggesting these processes are important.
Diagnosis
Since primordial dwarfism disorders are extremely rare, misdiagnosis is common. 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 the child is 5 years old and it becomes apparent that the child has severe dwarfism.
Treatment
There are as yet no effective treatments for primordial dwarfism.