Dr. Poongothai J. Sakthivel

Y chromosome microdeletions in sperm DNA of infertile patients from Tamil Nadu, South India

ABSTRACT: Infertility is a major health problem today affecting 10% to 15% of the couples and in these couples, male factor infertility accounts for ~50% of causes. The known causes of male infertility are quite numerous but can be grouped into a moderate number of major categories. It has been associated with several genetic and non-genetic conditions. Genetic causes of infertility are an important aetiological factor leading to irreversible partial or complete spermatogenetic arrest. Y chromosome microdeletions are a common molecular cause of spermatogenic failure. It has been identified in 9% of azoospermic, 7–10% of idiopathic severe oligozoospermic and 11.6% of severe oligoasthenozoospermic infertile patients. The microdeletions that occur in the AZF [AZoospermic Factor] region of long arm of Y chromosome affect genes that are involved in spermatogenesis. There are three recurrently deleted nonoverlapping subregions in proximal, middle and distal Yq11 regions in the deleted interval designated as AZFa, AZFb and AZFc. Recently a fourth region AZFd has been identified which lies between AZFb and AZFc. To date, most of all studies from India and the majority of studies worldwide have analyzed Yq microdeletions from DNA isolated from blood. However, blood DNA might not be representative of sperm DNA, which is of different embryological origin. Sperm DNA might have higher rate of deletions and DNA damage as a result oxidative stress. Only few studies have analyzed sperm DNA for Y chromosome microdeletions. Further, few markers confining to each AZF region was used in most of STS based Y chromosome microdeletion studies. We, for the first time made an attempt to assess the association of Y chromosome microdeletions among Tamilian men of South India with azoospermia, oligozoospermia and oligoasthenospermia using several STS makers from each AZF region and also aimed to determine whether the blood DNA microdeletion picture matches the semen DNA Yq microdeletion map. Samples of blood were collected from 45 infertile men; semen samples from 72 infertile men; paired samples (blood and semen of same patient) from 30 infertile men at infertility clinics from Erode and Nilgiri Districts of Tamil Nadu, South India. The patients were classified according to alterations detected in spermograms, based on the WHO technique (1999), into groups with oligozoospermia [69], asthenozoospermia [50], oligoasthenospermia [24], varicocele [1], azoospermia [1], teratozoospermia [1], and necrozoospermia [1]. 140 normozoospermic (> 20 million sperms /ml of semen) males [90 blood, 30 semen, 10 paired samples] of proven fertility served as controls. DNA was extracted from 10 ml of peripheral blood and from semen using standard procedures.

BIO: The author Dr. J.Poongothai holds the degree of M.Sc., in Biochemistry. She is a Doctoral fellow in Biotechnology. She is in collegiate service since 1999. Her areas of interest are Genetic engineering and Molecular Biology. She guided post graduate Biochemistry students for their dissertation work. She is a life member of Society of Biotechnologist, India and annual member of Indian Society of Human Genetics. She had published 7 papers in national and international journals. She had presented more than 10 papers in National/International conferences and had attended a number of conferences and workshops. Now, She is the Assistant Professor of Chemical Engineering and Material Science Department of Amrita Viswha Vidya Peetham, Coimbatore, Tamil Nadu, India.