Screening for Down syndrome
نویسندگان
چکیده
In 1866 J Langdon Down made the observation of a subgroup of patients with particular facial features and mental handicap in the outpatient department of the London Hospital 1. In the late 1950’s, it was shown that an extra acrocentric chromosome was present in persons with Down syndrome, resulting in a diploid chromosome number of 47. It is now known that Down syndrome results when either the whole or a segment of the long arm of chromosome 21 is present in three copies instead of two (Table 1). This can occur as a result of three separate mechanisms: nondysjunction (94% of cases), Robertsonian translocation (3.6%) and mosaicism (2.4%).
منابع مشابه
RELATIONSHIP BETWEEN THE SERUM LEVELS OF FOLIC ACID WITH THE RESULTS OF FIRST TRIMESTER DOWN SYNDROME SCREENING METHODS AND FETAL KARYOTYPE IN HIGH RISK PREGNANT WOMEN REFERRING TO THE ALZAHRA EDUCATIONAL HOSPITAL OF TABRIZ
Background & Aims: To investigate associations between serum levels of folic acid with the results of the first trimester Down syndrome screening methods and fetal karyotype in high-risk pregnant women. Materials & Methods: In this cross-sectional study, serum levels of folic acid in 232 high risk pregnant women were measured using ELISA method and Down syndrome screening was done using karyot...
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