title: Prenatal screening of cytogenetic anomalies - a Western Indian experience.
abstract: BACKGROUND
  Children born with congenital anomalies present a very high rate of perinatal death and neonatal mortality. Cytogenetic analysis is a convincing investigation along with clinical suspicion and biochemical screening tests. The current study was designed to characterize the prevalence and types of chromosomal abnormalities in high risk prenatal samples using different cytogenetic techniques.
  
  
  METHODS
  This study was conducted on a total of 1,728 prenatal samples (1,324 amniotic fluids, 366 chorionic villi and 38 cord blood samples) from 1994 to 2014 at Institute of Human Genetics, Ahmedabad, India. Conventional karyotyping was conducted with GTG-banding. Molecular approaches were used (fluorescence in situ hybridization = FISH and/ or array-comparative genomic hybridization = aCGH) when indicated to detect karyotypic abnormalities.
  
  
  RESULTS
  Abnormal karyotypes were detected in 125/1,728 (7.2%) cases. Trisomy 21 was the most common abnormality detected in 46 (2.7%) followed by trisomy 18 in 11 (0.6%) and trisomy 13 in 2 (0.1%) samples. Besides, structural abnormalities such as reciprocal and Robertsonian translocation were detected in 20 [1.2%] cases. Turner syndrome was diagnosed in seven (0.4%) cases; in six (0.34%) cases there was an inversion in the Y-chromosome. Heteromorphic variants were diagnosed in 22 (1.3%) cases. Finally, small supernumerary marker chromosomes (sSMC) were found in six (0.34%) cases.
  
  
  CONCLUSIONS
  Conventional GTG-banding along with molecular cytogenetic techniques is useful in detecting genomic alterations and rearrangements. Comprehensive characterization of chromosomal rearrangements like sSMC has the potential to save potentially healthy fetuses from being terminated.
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. fshethad1@googlemail.com.
authors.forename: Frenny
authors.initials: F
authors.lastname: Sheth
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. mizan142004@yahoo.com.
authors.forename: Mizanur
authors.initials: M
authors.lastname: Rahman
authors.affiliation: Institute of Human Genetics, Jena University Hospital, Kollegiengasse 10, D-07743, Jena, Germany. thomas.liehr@med.uni-jena.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. manisharushik@yahoo.co.in.
authors.forename: Manisha
authors.initials: M
authors.lastname: Desai
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. bhumi2311@yahoo.com.
authors.forename: Bhumika
authors.initials: B
authors.lastname: Patel
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. chiragmdi8@gmail.com.
authors.forename: Chirag
authors.initials: C
authors.lastname: Modi
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. drsuniltrivedi@hotmail.com.
authors.forename: Sunil
authors.initials: S
authors.lastname: Trivedi
authors.affiliation: FRIGE's Institute of Human Genetics, FRIGE House, Satellite, Jodhpur Gam Road, 380015, Ahmedabad, India. jshethad1@gmail.com.
authors.forename: Jayesh
authors.initials: J
authors.lastname: Sheth
mesh_terms: D000328:Adult; D000649:Amniocentesis / Q000379:methods; D015193:Chorionic Villi Sampling / Q000379:methods; D025063:Chromosome Disorders / Q000175:diagnosis / Q000453:epidemiology; D055028:Comparative Genomic Hybridization / Q000379:methods; D017218:Cordocentesis / Q000379:methods; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D007194:India / Q000453:epidemiology; D007621:Karyotyping / Q000379:methods; D017063:Outcome Assessment, Health Care; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors