Abstract:
For various reason, Pakistan is a fertile and suitable country for studying hereditary disorders families one from Rawat, Punjab, and one from Panjgur, Balochistan, showing hereditary disorders have been studies by constructing extensive pedigrees and X-raying for patient for describing the skeletal defects.
The family from Rawat, Punjab, showed multiple cartilaginous exostosis (diaphyseal aclasis). This trait seems to follow autosomal mode of inheritance with probably complete penetrance i.e., defective gene invalidly expresses itself, and variable expression i.e., in different patient different bone are involved. In condition with this type of inheritance, in case of sibships (i.e., offspring consisting of brother and sisters) containing affected persons, at least one of their parents is effective as well.in cases where one parent is affected with a single defective gene and other is normal, on average half of the children from such marriages are likely to show defeats. In this disorder, numerous bony lumps become evident between 3-5 years of age. The bony excrescences generally appear on the long bones of the limbs usually toward their ends resulting in various deformities such as shortness of stature, asymmetry of shoulder girdles, bowing of forearm and dislocation of wrist and elbow joints and deformed knee joints. Some patients showed osteoporosis. (i.e., reduction in the amount of bone mass) and flexion deformity of the interphalangeal joints i.e., they could not take make a tight fist.
The family from Panjgur, Balochistan, showed dwarfism and skeletal defects of the spine and limbs. The condition was diagnosed as spondyleopimetaphyseal dysplasia. In all 19 person, 12 males and 7 females, were found to be affected. Analysis of the pedigree is strongly suggestive of autosomal recessive inheritance which means that the trait manifests itself when both the parents, through themselves apparently normal, carry and transmit gene defective gene to their offspring, resulting in both the copies of the gene being defective. In case, one parent is affected and the other a carrier, on average half of the children from such a marriage are expected to be affected. In order to avert the recurrence of the disorder, it is advisable that marriage between relatives be strictly avoided.
Such study provides sound basis for genetic counselling with a view to controlling the hereditary disorders.
