(Posted:16-Jun-2015)

Down syndrome: It is the most common chromosomal disorder. Karyotyping features: 1) Trisomy-21 type: About 95% have a complete extra chromosome 21(47,XY + 21). 2) A translocation variant:Making up 4% of all cases,has extra chromosal material derived from inheritance of a parental chromosome bearing a translocation of the long arm of chromosome 21 to chromosome 22 or 14. 3) Mosaic variants:Make up about 1% of all cases.They have a mixture of cells with normal chromosome numbers and cells with an extra chromosme 21. Clinical features: 1.Mongoloid facies: Brachycephaly with flat occiput. Small head ,flat round face. Depressed nasal bridge Inner epicanthal fold Protruding tongue. 2. Ocular system: Brushfield spots. Congenital cataract. Nystagmus. Strabismus Refractive errors Cataract after 25 years of old. 3. Ears: Small,low set. Deafness. 4. Hands and feet: Simian crease. Short broad hands. 5. Central nervous system: Mental retardation. Hypotonia. 6. Psychiatric: Reactive depression in adolescent and young adults. 7. Cardiovascular system: Congenital heart disease mainly in septal defect. Hirsuprung disease. 8. Genitalia: Small penis. Cryptorchidism. 9. Immune system: Frequent infection. Autoimmune disease. 10. Endrocrine: Congenital hypothyroidism. Girls fertile & boys sterile. 11. Respiratory: increase incident of pneumonia due to decrease immunity. 12. Increase risk of umbilical hernia. 13. Generalized muscular hypotonia. 14. Increase gap between first and second toe. 15.General: Short stature. Counselling: Parent of a child with down syndrome should be counseled with tact,compassion and truthfullness. The parents should be told about the associated problems,and the importance of early stimulation should be highlighted. The risk of recurrence should be clearly told to be parents.