Down Syndrome In Nigeria

The Cause and Effect of Down syndrome in Nigeria

Introduction

Down syndrome has been a naturally occurring chromosomal arrangement that has always been a part of human condition, irrespective of the human races, gender or socioeconomic lines that has been present in whole the universe. Down syndrome has also been defined as “Down syndrome is a set of physical and mental traits caused by a gene problem that happens before birth. Children who have Down syndrome tend to have features, such as a flat face and a short neck.” (john 2014). Common symptoms of Down syndrome include: shortened hands and fingers, small head, ears and mouth, and poor muscle tone. Children with Down syndrome lack the ability to sit, stand or walk and they are slow learners.

About 90% of the incidence was recorded among youthful mothers. “Studies of Down's syndrome covering a period of 9 years revealed an incidence of 1 in 865 live births in a Nigerian hospital. Cytogenetic analysis in 386 patients in Nigeria indicates that 369 (95.5%) cases are as a result of trisomy 21, nine cases(2.5%) are as a result of translocation trisomy 21, 6 cases (1.5%) are as a result of mosaics and the remaining 2(0.5) cases were classified as miscellaneous. (A. ADEYOKUNNU 1982). Down syndrome as a genetic disease affects many babies in Nigeria. The effect is due to a change in baby's chromosome i.e. having extra or abnormal

Human cells normally have 23 pair of chromosomes in which one pair of the chromosome comes from the mother and the other pair comes from the father. 95% of individuals that suffer from Down syndrome have three copies of chromosome 21(trisomy 21). This is caused by “nondisjunction” i.e. when one pair of the chromosome does not divide and the whole pair of the chromosome goes to one spot (Len Leshin 2009). This disorder occurs when chromosomes fail to segregate properly during meiosis I or meiosis II. Down syndrome can either be trisomy 21, mosaic Down syndrome or translocation Down syndrome. Trisomy 21 is when the patient has extra copy of chromosome 21 instead of the usual 2 copies in all cells. In the case of mosaic Down syndrome which is very rare, “patient has some cells that contain extra copy of chromosome 21 which is caused by abnormal cell division after fertilization” (staff 2014). Translocation Down syndrome occurs when part of chromosome 21 becomes attached to another chromosome before or at fertilization. Female with extra copy of chromosome 21 is “designated with the code 47,XX,+21 while a male with extra copy of the chromosome have the code 47,XY,+21” (Pasternak June,2005). Individuals with this disorder have 47 chromosomes instead of the normal 46