Who are the Dwarfs?
Achondroplasia, also called short limbed dwarfism, is the commonest cause of dwarfism in the community. Up to 70% of the dwarfs in the community belong to this category. In achondrplasia there is a defect in converting cartilage to bone, a process called ossification, particularly in the long bones of the arms and legs resulting in short arms and legs. The other characteristic features are an enlarged head with a prominent forehead, limited range of motion at the elbows and short fingers. The ring finger and the middle finger may diverge, giving the hand a trident appearance. The persons afflicted with achondroplasia are of normal intelligence and lead fruitful lives.
Cretinism is a condition that is produced in infants and children due to lack of the thyroid hormone which could result from a congenital defect, lack of iodine in the diet or if the thyroid gland is diseased or surgically removed. Cretinism causes serious retardation of the physical and mental development. If left untreated the cretin evolves into the Moron, Idiot or Imbecile of an adult with the stature of a dwarf. The nose is flattened, abdomen is protruded, the skin is thick and flabby and there is slowness of movement and speech, with a low IQ. If detected and treated in infancy or childhood, the physical and mental growth would become normal.
Pituitary dwarfism is due to dysfunction of the pituitary gland, a pea sized mass of tissue at the base of the brain. The pituitary gland is functionally divided into an anterior pituitary and a posterior pituitary. The anterior pituitary secretes the growth hormone, thyroid stimulating hormone, follicle stimulating hormone, luteinizing hormone, adrenocorticotrophic hormone and prolactin. The posterior pituitary secretes the anti diuretic hormone and oxytocin. Pituitary dwarfs are perfectly proportioned and are of two types. The first type is due to a deficit of all the anterior pituitary hormones (panhypopituitarism) resulting in a generalized slow growth without sexual maturity. They form two thirds of the cases. The second type (one third) is due to an isolated deficiency of the Growth hormone. They mature sexually and can reproduce.
The African pygmy belongs to a subgroup of the second type of pituitary dwarfism. In these persons there is a hereditary inability to form somatomedin-C in response to stimulation by the growth hormone released by the anterior pituitary. Somatomedins are responsible for the actual growth of the bone and tissues and at least four are produced by the liver. There are different theories proposed to explain the short stature of pygmies. It has been suggested that it could be related to adaptation to low sunlight light levels in rainforests with little manufacture of vitamin D in the skin, thus limiting calcium uptake from the diet for bone growth leading to the evolution of the small stature. The other explanations include lack of food in the rainforest environment, low calcium levels in the soil and adaptation to heat and humidity.
Dwarfs face stigma and discrimination in society which is largely unfounded. The persons afflicted with achondroplasia, both types of pituitary dwarfs and the African pygmies live perfectly normal lives and contribute their mite to society. Cretinism should be detected in infancy or childhood and treated with hormones to ensure normal physical and mental development.
Written By: Dr. Pilli Samuel Rajkumar, MD (Hyderabad, India)
Edited by: Rajesh Bihani ( Find me on Google+ )