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Egyptian Journal of Medical Human Genetics

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Chromosomal study in newborn infants with congenital anomalies in Assiut University hospital: Cross-sectional study

YA Mohammed, RM Shawky, AS Soliman, MM Ahmed

Abstract


In 40–60% of congenital malformations, the cause is unknown. Genetic factors account for approximately 15%; environmental factors produce approximately 10%; a combination of genetic and environmental influences produces 20–25%. The study aims to document prevalence
and patterns of congenital malformations detected at birth in Assiut University hospital and clarify underlying chromosomal abnormalities of such malformations. Also possible predisposing factors will be studied.
Newborns with apparent congenital anomalies were selected from 5000 newborn infants delivered consecutively at the department of Obstetrics and Gynecology within 7 months. Full maternal history, family history, perinatal history, pedigree construction as well as clinical examinations and
investigations including karyotype were done. Congenital anomalies were found in 103 cases with a prevalence of 2.06% with male to female ratio of 1.7:1. Skeletal system anomalies had the highestfrequency (37.9%), followed in descending order by chromosomal abnormalities (27.2%), circulatory system anomalies (22.3%), central nervous system (CNS) anomalies (19.4%), genital organs anomalies (16.5%), gastrointestinal tract (GIT) anomalies (14.6%), eye and ear anomalies (8.7%), and lastly urinary system and others anomalies in 3.9% each. Breech presentation, perinatal asphyxia, incubator admission and the need for resuscitation were significantly associated with the presence of congenital anomalies. Higher prevalence of congenital anomalies was observed in neonates
of grand multiparous women, diabetic mothers delivery by CS, cases with oligohydramnios and with positive consanguinity. Chromosomal abnormalities were found in 28 cases (27.18% of malformed cases) (5.6/1000). Numerical abnormalities were found in 22 cases (21.35%) (4.4/1000), Down syndrome in 16 cases, Edward syndrome in two cases, Patau syndrome in one case and Turner syndrome (monosomy) in
three cases. Structural abnormalities were present in six cases (5.83%) (1.2/1000), Down syndrome in two cases, Turner syndrome in two cases, balanced translocation [(12;13)(q15;q34)] with dysmorphic features and undescended testis in one case and deletion 9(q11;q31) with disorder of sex development in one case. To conclude karyotype should not be done routinely for all malformed cases as many of them are due to genetic syndromes. So, it is more useful to consult expert dysmorphologists for proper syndrome identification and for the decision to use more recent molecular techniques for diagnosis.



http://dx.doi.org/10.1016/j.ejmhg.2011.02.003
AJOL African Journals Online