الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 171 |  |  |
| | | from | 171 | | |
Abstract
Summary & Conclusion Down syndrome (DS), also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is the most common chromosomal anomaly among live-born infants. It is typically associated with a delay in both cognitive ability (mental retardation) and physical growth, and a particular set of facial characteristics. Individuals with DS are at increased risk for several endocrinological conditions, including hypothyroidism, growth retardation, diabetes mellitus, and obesity. They have several features in common with growth hormone (GH) deficient subjects. With the increase in the life expectancy of people with DS, growth retardation and its related morbidity and mortality are emerging as important long-term consequences. DS may be associated with congenital anomalies as congenital heart disease Accounts for 50-60% of DS that mostly may be endocardial cushion defect then ventricular septal defect, gastrointestinal tract anomalies, ear canal stenosis and thyroid dysgenesis. Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a protein that in humans is encoded by the IGF-1 gene. IGF-1 is a hormone similar in molecular structure to insulin. It plays an important role in childhood growth and continues to have anabolic effects in adults. A synthetic analog of IGF-1, mecasermin is used for the treatment of growth failure. IGF-1 consists of 70 amino acids in a single chain with three intramolecular disulfide bridges. IGF-1 has a molecular weight of 7,649 daltons.