A road less known....lesser asked for…least travelled

Medically reviewed by Dr. Ganesh Pujari

1990 – A 32 year old female in the 22^nd week of pregnancy. Antenatal scan normal. Triple screen results suggestive of Down syndrome. The obstetrician was in a dilemma either to continue or terminate the pregnancy. Finally, at term, delivered a dysmorphic baby. Clinically, Down syndrome.

2020 – Another case with the same history. At 16^th week amniocentesis done for karyotyping. Amniotic fluid karyotyping revealed trisomy 21. Confirmed by FISH. Parents counselled. Pregnancy terminated.

The above two case scenarios encompass the metamorphosis which diagnostic medicine has been through in the past 2-3 decades. Many newer investigation modalities daily sprung up in the never-ending quest of perfect predictability at both diagnostic and prognostic fronts. One such unexplored niche in Cytogenetics.

Cytogenetics is the study of chromosomes. Chromosomal abnormalities are an important cause of genetic disease and may be seen in a variety of conditions such as mental retardation, dysmorphism and abnormal development, disordered sexual development, recurrent abortions, infertility and cancer. In many cancers, especially leukaemia, identification of chromosomal abnormalities is essential for making a diagnosis, planning specific treatment, and determining prognosis. Cytogenetic analysis is an important component of prenatal diagnosis and it also helps in the diagnosis of chromosome breakage syndromes like Fanconi’s anaemia. It covers a whole range of techniques like conventional karyotyping, Fluorescence In Situ Hybridization (FISH), Multiplex Ligase-based Probe Amplification (MLPA) and Comparative Genomic Hybridization (CGH commonly known as arrays). These procedures can be performed on peripheral blood, bone marrow, amniotic fluid, chorionic villus, products of conception, tumour tissue and skin samples.

The Cytogenetics department at Aster Labs is actively involved in all aspects of tissue processing including cell culture, harvesting, and analysis of chromosomes by light and fluorescence microscopy. The department has technologists trained from reputed institutions like CMC, Vellore. They are well-versed with the morphology of normal and abnormal chromosomes and cytogenetic nomenclature.

To sum up, Cytogenetics is a new path emerging on the vast, uncanny terrains of diagnostic medicine, thereby not only enabling clinicians with the much sought after diagnosis but also offering the neophyte pathologists and anatomists an altogether unexplored niche to take up as a sustainable, rapidly upcoming and at par alternative to conventional streams of histopathology, cytology and laboratory haematology.