Evolution of the Field of Medical Genetics
Over the past decade, remarkable progress has been made in the field of medical genetics. The development and integration of new testing technologies — whole exome sequencing (WES) and whole genome sequencing (WGS) — accelerated the discovery of genetic conditions and massively improved their diagnosis and management.
As a result, the role of the genetic counselor has also become increasingly pivotal as they provide guidance through the sometimes complex diagnosis and management process between the laboratory service, physician, and patient. They help patients better understand and adapt to the medical, psychological and familial implications of their genetic disorders; and, help facilitate informed decisions in a personalized manner. The Unified Healthcare Professional Qualification Requirements1 — issued by the UAE Ministry of Health and Prevention, the Department of Health Abu Dhabi, and the Dubai Health Authority — stipulate that in order to obtain a license to practice in the UAE, genetic counselors should hold a master’s degree in genetic counseling.
Rifaat Rawashdeh, a Licensed Certified Genetic Counselor with National Reference Laboratory (NRL) who has previously worked as a Molecular Laboratory Genetic Counselor at Emory Genetics Laboratory in Atlanta, USA, and as a Senior Genetic Counselor at the King Faisal Specialist Hospital & Research Centre in Riyadh, Saudi Arabia, explains: “With the significant increase in the number of genetic tests now available and requested, there has been a parallel increase in the complexity of test ordering. Consequently, there is a need to assist non-genetic providers – who may not be fully familiar yet with the latest technology innovations – with results interpretation. Genetic counseling has emerged as a discipline to bridge this gap, and genetic counselors are now an integral part of today’s healthcare system.”
Genetic Disorders in the UAE
As in most Arab countries, there is a high incidence of genetic disorders in the UAE. The database of the Center of Arab Genomic Studies reports approximately 360 different genetic disorders present within the UAE population.2 The most common are hemoglobinopathies such as β-thalassemia, α-thalassemia and sickle cell disease. Other common genetic disorders in the country include G6PD, metabolic disorders, hearing impairments, hereditary cancer syndrome, congenital abnormalities, intellectual disabilities and developmental delays, chromosomal syndromes and cystic fibrosis.
Approximately 60 per cent of all genetic disorders in the UAE are autosomal recessive,3 meaning a child has inherited one copy of a defective recessive gene from each parent, which has resulted with development of the disorder.
This high frequency of autosomal recessive disorders is due to many factors including: consanguinity; large family sizes, which increase the chances of children inheriting a disorder or becoming carriers if the parents are carriers; gene pool homogeneity; lack of awareness of the importance of undergoing genetic counseling to better understand potential carrier risks; and, the prevalence of founder mutations, which is defined as a group of patients in a certain geographical area having a particular genetic disorder as a result of a common mutation inherited from a common ancestor.
Rawashdeh elaborates: “For example, the Sanjad-Sakati syndrome is a rare autosomal recessive disorder in the Middle East wherein people who have this disorder have two copies of the common founder mutation. It is believed to be an ancient mutation, inherited thousands of years ago. Features of this syndrome include severe challenges in growth and development, congenital hypoparathyroidism, dysmorphic features, and mild to severe intellectual disability.”
The Era of Personalized Genomic Medicine and Genetic Counseling
Personalized genomic medicine, also referred to as precision medicine, is an emerging field where diagnosis and medical management is customised to each patient based on their genetic information, family history, and lifestyle. A patient’s unique genomic data combined with environmental factors, imaging, family history and other screening testing, yield a personalized insight into their susceptibility to disorders and response to treatment.
With its increased affordability, whole genome sequencing is now an essential tool in precision medicine. It enables the detection of variations in the human genome that can signal the risk of acquiring certain disorders before clinical signs and symptoms appear.
Examples of these include cancers, cardiovascular diseases, diabetes, chronic liver diseases, neurological and metabolic disorders. Early detection allows for planning strategies of prevention and early intervention for enhanced patient management. This is evident in women with germline mutations in BRCA1 & BRCA2 genes who have a 36 per cent to 85 per cent lifetime chance of developing breast cancer, and a 25 per cent to 60 per cent chance of developing ovarian cancer. Based on this genomic risk, intensive surveillance programs, such as increased frequency of mammograms or even prophylactic surgery including mastectomy and removal of the ovaries, are warranted.
Another application and major benefit of personalized genomic medicine is the field of pharmacogenomics. Pharmacogenomics is the science of examining specific genomic variations and their effect on an individual’s response to drugs, which provides physicians with a great advantage in selecting suitable therapies; this in turn improves outcomes while minimising side effects and toxicity in a personalized manner. Warfarin (Coumadin) — a well-known anticoagulant — is associated with a high incidence of over-anticoagulation with resultant bleeding, which limited its wide use for patients who can benefit from this therapy. It was found that genetic variants in two genes (CYP2C9 and VKORC1) are known to influence the appropriate warfarin dose for different patients.4 As a result, the U.S. Food and Drug Administration (FDA) has encouraged physicians to use genetic testing to recommend the appropriate warfarin dosing for their patients to increase drug efficacy and reduce undesirable side effects.
Genetic counselors play a major role and are a key component of precision medicine, with their unique set of skills and expertise in genetics, genomics, risk assessment, and communication.
Increased Demand for Genetic Counselors in the UAE
According to Rawashdeh, genetic counseling services are currently underserved in the UAE and should be expanded. “There are many reasons why a patient would be referred to a genetic counselor. Therefore, there is a high demand for medical professionals in this specialty who are trained to accurately order, interpret and communicate the results of genetic tests.”
Rawashdeh continues: “Also, there are social factors that occur where patients may be in denial, or they do not wish to be referred to a genetic counselor to avoid stigma. Although this is gradually changing, collectively we need to do more to educate patients and increase their awareness of the benefits of genetic counseling. This will encourage potential carriers and their families to visit a genetic counselor for support and guidance to make informed decisions regarding testing options, interpretation of test results, prevention, and life planning. Counselors not only offer guidance, but they also refer patients and their families to other medical specialties, advocacy, and support groups to help them effectively manage their condition.”
As personalized medicine continues to evolve, the role of the genetic counselor will become increasingly important, and the field of genomic counseling will become even more pivotal to improving health outcomes.
“In the UAE, significant progress has been made in the application of advanced genetic testing in an effort to ensure patients receive the highest standards of care across every medical specialty. I would be glad to see the creation of an internationally accredited genetic counseling training program in the UAE, to complement these efforts and increase the number of licensed and certified genetic counselors in the country,” concludes Rawashdeh.
References
1) Department of Health Abu Dhabi. (2017). Unified Healthcare Professional Qualification Requirements. [online] Available at: https://www.haad.ae/HAAD/LinkClick.aspx?fileticket=2K19llpB6jc%3D&tabid=927 [Accessed 12 July 2018].
2) Center for Arab Genomic Studies. (2018). CTGA Database Listing. [online] Available at: http://www.cags.org.ae/ctga/listing.aspx?sid=78e1abf42e1b4dd
4ac82aba309c79ee7 [Accessed 10 May 2018].
3) Teebi A, Farag T (eds), Genetic Disorders among Arab Populations, New York, Oxford University Press, 1997, pg341–372
4) Sconce, EA at al. (2005) The impact of CYP2C9 and VKORC1 genetic polymorphism and patient characteristics upon warfarin dose requirements: proposal for a new dosing regimen. Blood. 1;106(7), p. 2329-33. Epub