Primordial dwarfism (PD) is a 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 3–5 years of age. Medical professionals typically diagnose the fetus as being small for gestational age, or as showing intrauterine growth restriction when an ultrasound is conducted. Typically, people with primordial dwarfism are born with very low birth weights. After birth, growth continues at a much slower 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 among the most severe forms of the 200 types of dwarfism. There are as yet no effective treatments for primordial dwarfism. It is rare for individuals affected by primordial dwarfism to live past the age of 30. In the case of microcephalic osteodysplastic primordial dwarfism type II (MOPDII), there can be increased risk of vascular problems, which may cause premature death. 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.
Transient erythroblastopenia of childhood (TEC) is a slowly developing anemia of early childhood characterized by gradual onset of pallor. Signs and symptoms
Individuals with TEC have a median age of presentation of 18–26 months; however, the disorder may occur in infants younger than 6 months and in children as old as age 10 years. Because of the gradual onset of the anemia, children are often healthier than expected from their low hemoglobin levels. Cause
The cause of TEC is unknown, but it thought to be triggered by a viral infection. While rare cases have been attributed to infection with Parvovirus B19, the majority of cases are not related to Parvovirus infection. This is in contrast to transient aplastic crisis, seen in patients with hemoglobinopathies such as sickle cell disease, which is usually caused by Parvovirus infection. Diagnosis
Children typically present with a moderate normocytic anemia (usual range: Hemoglobin 5-8 g/dL) and reticulocytopenia. Mean corpuscular volume (MCV) is usually normal for age. Hemoglobin F levels are also typically normal. Prognosis
Most patients recover completely within 1–2 months. However many reported cases have lasted 18–24 months and longer. References
External links
ped/2279 at eMedicine