MEDISCAN - CHENNAI, Genetic counseling

Genetic counseling is the process by which patients or relatives at risk of a disorder that may be hereditary are advised of the consequences of the disorder, the probability of developing or transmitting it and of the ways, in which this may be prevented, avoided or ameliorated. (Courtesy - Peter S. Harper)

Four Categories of Counseling:

Premarital / Prenatal counseling

People with family /personal history of physical / mental deformities with or without consanguinity are offered counseling regarding the probability of the risk they carry for the particular disorder.

Example: Mr. x and Mrs. x came for premarital counseling. They were first cousins. Ms X had lost her brother at 20 years of age. The boy was born at term, had birth asphyxia, neonatal jaundice and convulsions from day 4. All motor and mental milestones were delayed. He was kept stable on anticonvulsants. He was admitted for prolonged and recurrent seizures at age seven. The possible diagnosis after a series of investigations was Adrenoleukodystrophy. There was neuroregression from 12 years of age. The boy progressively lost acquired milestones. He died at 20 years of age. There are no other affected members in either side of the family. The exact etiology of his condition is not clear. Adrenoleukodystrophy is an X linked disorder. 50% of female offsprings could be carriers and 50% of male offsprings could be affected. However, no confirmatory diagnosis has been done. Hence we will not be able to predict the risk of a similar nature in his sister's offsprings.

We have done karyotyping for Ms X and Mr. X to rule out chromosomal abnormalities. The reports are normal. We have started her on periconceptional folic acid and Vitamin B12 supplement from now onwards.We extend our best wishes to the couple. They may contact us for further advice when her pregnancy is confirmed.

Antenatal Counseling

A woman carrying a pregnancy with a structural anomaly is counseled along with her husband and family regarding the anomaly and the prognosis of the fetus facilitating the couple to make decision with the informed choices accordingly.

Down's Syndrome: As advanced maternal age carries a natural risk for Down syndrome (the most common mental retardation) women above 35 years are counseled to have the screening tests to find out their relative risk for the problem.
Pure Trisomy 21 is a type of Down's Syndrome with a recurrence risk of less than 1% in siblings.

Indirect testing - First Trimester Screening at 11 - 12 weeks of gestation, to assess the risk for chromosomal aberrations.

Direct testing - chorionic villus sampling at 11 - 13 weeks / amniocentesis at 16 - 20 weeks to rule out chromosomal anomalies in the fetus.

Pregnant women, who need to undergo prenatal invasive procedures, are counseled before the procedure to make them understand the need for these procedures and the risks involved and also the limitations in any of these procedures.

Work up of Index case with anomaly

Parents with an affected child are offered counseling. The nature of the problem of the previous child and its recurrence risk. Is worked up and explained to the parents. If diagnosis is not assigned for the index child, the child is subjected to diagnostic tests. In case of an ongoing pregnancy prenatal diagnosis is attempted to diagnose the problem in the fetus. This process facilitates the parents to know that the current pregnancy is normal or carries a baby with the same defect.. The state of the art Cytogenesis laboratory and the Clinical laboratory of the organization cater to these patients. For molecular diagnosis of specific and rare genetic disorders samples are sent abroad for diagnosis.

Example: A couple had come to us for pre pregnancy counseling. On reviewing their history, both their children were affected with Farber's disease. Farber's disease is a metabolic disease due to Ceramidase enzyme deficiency. We had contacted laboratories abroad where enzyme estimation as well as mutation analysis are being done. Since it is a very rare disease, very few laboratories are involved in this process.

One of the professor in France - Dr. Levade was willing to do the test at free of cost (patient belonged to a low socio economic group) parents sample along with the child's blood sample was sent to France and there it was detected as Farber's disease. With this index child's work up, now we can proceed with the prenatal diagnosis in the subsequent pregnancies. Presently the mother has an ongoing pregnancy and Prenatal is planned in January 05. This will be first prenatal procedure in INDIA for Farber's Disease

Fetal autopsy counseling

Also parents with complete work up of previous bad pregnancy outcome with postmortem report of the previous child or with bad obstetric history are also counseled in detail and guidance given for planning the next pregnancy.

Related services

Apart from counseling services and meticulous documentationof records all patients, the department is also actively involved in the activities of the Birth Defects Registry of India and the Support Group for MPS. The Cytogenetics Laboratory and the Fetal Pathology Unit of the organization work in unison with the counseling department for the benefit of the patients.