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Prenatal screening of cytogenetic anomalies - a Western Indian experience

Frenny Sheth1, Mizanur Rahman2, Thomas Liehr3

  • 1FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. fshethad1@googlemail.com.

BMC Pregnancy and Childbirth
|April 18, 2015
PubMed

Insights

Prenatal cytogenetic analysis detected chromosomal abnormalities in 7.2% of high-risk samples. Trisomy 21 was most common, highlighting the importance of comprehensive genetic testing for congenital anomalies.

Area of Science:

  • Genetics
  • Prenatal Diagnostics
  • Human Genetics

Background:

  • Congenital anomalies lead to high rates of perinatal and neonatal mortality.
  • Cytogenetic analysis is crucial for diagnosing these conditions, alongside clinical and biochemical screening.
  • This study investigates the prevalence and types of chromosomal abnormalities in high-risk prenatal samples.

Purpose of the Study:

  • To characterize the prevalence and types of chromosomal abnormalities in high-risk prenatal samples.
  • To evaluate the utility of different cytogenetic techniques in prenatal diagnosis.
  • To identify common and rare chromosomal aberrations in a prenatal cohort.

Main Methods:

  • Analysis of 1,728 prenatal samples (amniotic fluid, chorionic villi, cord blood) from 1994-2014.
  • Conventional karyotyping using GTG-banding.
  • Molecular cytogenetic techniques, including fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (aCGH), were employed when indicated.

Main Results:

  • Abnormal karyotypes were found in 7.2% (125/1,728) of cases.
  • The most frequent abnormality was Trisomy 21 (2.7%), followed by Trisomy 18 (0.6%) and Trisomy 13 (0.1%).
  • Structural abnormalities (translocations, inversions), Turner syndrome, and small supernumerary marker chromosomes (sSMC) were also identified.

Conclusions:

  • Conventional and molecular cytogenetic techniques effectively detect genomic alterations and rearrangements.
  • Comprehensive characterization of chromosomal abnormalities, including sSMC, aids in accurate prenatal diagnosis.
  • Accurate diagnosis can prevent the termination of potentially healthy fetuses.
Abstract

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