Makle factor defects and role of genes

Do you know that as much as 80% of all male infertility may have a genetic basis”:

Where from money will come for gene testing ?? “Couple face overwhelming financial and emotional costs related to their infertility ,and given the present diagnostic uncertainties they also face difficult choices.

Q.1. Why so much expensive tests on genetic assessment in a case of subfertile men?

“There is a strong speculation across the globe that as much as 80% of all male infertility may have a  genetic basis”: Source:-“  Infertility in the Male”- 4^th Ed. Ed by Larry I. Lipshultz et al, Cambridge University Press,, ISBN- 978-0-521-18122-8; -----In India available at Cambridge House, 4381/4,4, Ansari  Road, Daryaganj, New Delhi, 110 002.-pp. 646

Q.2. what are the different methods of Lab. Assessment of Chromosomal disorders? Skilled cytologist is essential.

1) Conventional age-old G-band analysis –Full Karyotyping has a resolution of 5-10 mega base pairs (Mb) –takes 10-21 days-Parental anxiety in cases of prenatal diag and TOP if finally indicated.

 2) QF-PCR: - Quantitative Fluoresrescence  PCR    :-Reports are available by 48-76 hours; It is usually done for Trisomy 18, 21. 13 from CVS or Amniotic cells. Polymerase Chain Reaction: - to target specific whole chromosomal anomaly. It came in early 1990. Designed typically for Trisomy 13, 18, 21, and sex chromosomal abnormalities. Reports were cheap and available by 48-76 hours. In prenatal tests for instance results are available, therefore minimal Parental anxiety. Especially when serum biomarkers and .or sonographic soft markers are positive. (High-risk screening result).  Many Labs are depending on this test alone if screening results are +ve in serum or soft markers age +ve. and performing time consuming Karyotype only when

 3) FISH (Fluorescence in Situ Hybridization)

 It is employed only in high degree of a particular chromosomal malformation is suspected. This technique identifies a) interstitial sub-microscopic microdeletions  b) Micro duplications C) Subteloromic  deletions and 4) Duplications.

One should remember that FISH and QF-PCR are ‘targeted approaches to gene disorders’ – therefore assess only limited number of loci. If  someone send samples from CVS/Liquor  Amino –then referring physician should furbish a history and probable genetic/Chr disorder he is expecting in the  offspring.

D) aCGH (Comparative genomic Hybridization):

Microarray this utilizes uncultured cells and reports are available by 10 days .time. Automated analysis

–The high resolution used –allows detection of submicroscopic deletions or duplications-. Different types of probes are available:

a)  BAC- Bacterial artificial clones 100-200kb in sizes. - Only targeted for known regions of microdeletions. Or duplication syndromes.

b) Synthetic oligonucleotide probes: - -25 used. These are high resolution-allows flexibly in selection of probes.-75 bp (base pair) are used

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