Int J Anat Res 2018, 6(3.3):5682-85. ISSN 2321-4287 5682 Original Research Article APPLICATION OF KARYOTYPING AND FLOURESCENT IN SITU HYBRIDISATION IN DETECTION OF KLINEFELTER SYNDROME Anjali Shastry * 1 , Preetha Tilak 2 , Amudha Subramaniam 3 . ABSTRACT Address for Correspondence: Dr. Anjali Shastry, Tutor, Department of Anatomy, St Johns Medical College, Bangalore, Karnataka, India. E-Mail: anju_shas@yahoo.com Introduction: Klinefelter Syndrome is one of most common sex chromosomal abnormality in males with incidence of 1 in 600 live births. Fluorescence in situ hybridization (FISH) is a powerful molecular cytogenetic technique which allows rapid detection of aneuploidies on interphase cells and metaphase spreads along with conventional GTG banding technique. Aims and objectives: To evaluate application of karyotyping and FISH as important diagnostic tool in diagnosis Klinefelter Syndrome. Materials and Methods: A retrospective study was conducted on 44 patients who were referred for karyotyping and counselling with suspected Klinefelter Syndrome and hypogonadism to Division of Human Genetics, Department of Anatomy, St. John’s Medical College, Bangalore from January 2014 to October 2017. Chromosomal preparations were done using the peripheral lymphocyte culture method followed by GTG banding technique, automated photography and karyotyping. FISH was performed with dual colour X/Y probes once abnormality was detected using GTG banding technique. Results: Out of 44 patients, 9 had typical karyotype of Klinefelter syndrome (47,XXY) and Four had variants of Klinefelter syndrome Conclusion: We can conclude that cytogenetic analysis forms important investigation in diagnosis , treatment and fertility status in patients with Klinefelter syndrome. KEY WORDS: Fluorescence in situ hybridization (FISH), Klinefelter Syndrome, Sex chromosome, Cytogenetic technique. INTRODUCTION International Journal of Anatomy and Research, Int J Anat Res 2018, Vol 6(3.3):5682-85. ISSN 2321-4287 DOI: https://dx.doi.org/10.16965/ijar.2018.310 Access this Article online Quick Response code International Journal of Anatomy and Research ISSN (E) 2321-4287 | ISSN (P) 2321-8967 https://www.ijmhr.org/ijar.htm DOI-Prefix: https://dx.doi.org/10.16965/ijar DOI: 10.16965/ijar.2018.310 *1 Tutor, Department of Anatomy, St Johns Medical College, Bangalore, Karnataka, India. 2 Junior consultant, Department of Anatomy, St Johns Medical College, Bangalore, Karnataka, India. 3 Tutor, Department of Anatomy, St Johns Medical College, Bangalore, Karnataka, India. Received: 06 Jul 2018 Peer Review: 06 Jul 2018 Revised: None Accepted: 13 Aug 2018 Published (O): 05 Sep 2018 Published (P): 05 Sep 2018 Journal Information ICV for 2016 90.30 Article Information had gynecomastia. About 80% of KS patients show a 47,XXY karyotype, 20% have other numeric sex chromosome abnormalities (48,XXXY, 48,XXYY, 49,XXXXY), 46,XY/47,XXY mosaicism, or structurally abnormal sex chromosome. Frequency of 48,XXXY & 48,XXYY is around 1 in 17000 to 1 in 50000 male births and frequency of 49,XXXXY being 80,000 to Klinefelter Syndrome is one of most common sex chromosomal abnormality in males with inci- dence of 1 in 600 live births. Klinefelter syn- drome (KS) was first described by Harry F. Klinefelter in 1942 in 9 men with testicular abnormalities who failed to produce sperm and