genetic counseling ... ultrasound examination: neural tube defects, trisomy 21, trisomy 18 آ¢...
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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
Empowering patients and providers through information and support
Genetic disorders are found in all medical specialties and can affect all patients; young and old, male and female, those unaware of underlying illnesses and those diagnosed with life-limiting conditions. Technological advancements now facilitate our ability to detect a genetic variation with accuracy and at a reduced cost. For this reason, there is an increased need for genetic couseling services as part of patient-focused programs in all healthcare facilities
By Deepa Narwani, Editor
GENETIC COUNSELING / EMPOWERING PATIENTS
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
Common indications for referral to a genetic counselor (Fig 1)
General Adult Genetics or Pediatric Genetics ¢ A chromosomal disorder: Down syndrome, Edwards syndrome ¢ A monogenic disorder: fragile X syndrome, Rett syndrome ¢ Visual loss or a congenital eye defect: retinitis pigmentosa, microphthalmia, early-
onset macular degeneration, cataracts ¢ Significant hearing impairment not secondary to recurrent otitis media ¢ A progressive neurologic condition: peripheral neuropathy, unexplained myopathy,
progressive ataxia, early onset dementia, familial movement disorder ¢ A progressive muscle weakness: muscular dystrophy, spinal muscular atrophy,
myotonic dystrophy ¢ Skeletal dysplasia or short stature: osteogenesis imperfect, achondroplasia ¢ An unexplained intellectual disability, global developmental disorder or autism ¢ Abnormal sexual maturation or delayed puberty ¢ An inherited bleeding disorder: hemophilia, thrombophilia ¢ An immune deficiency: Severe Combined Immunodeficiency (SCID) ¢ A kidney disorder: polycystic kidney disease ¢ A child with a metabolic disorder ¢ An abnormal newborn screening test result ¢ One or more birth defects: heart defect, cleft lip & palate etc.
Preconception Genetics or Prenatal Genetics ¢ An abnormal prenatal diagnostic test result, abnormal NIPT or abnormal prenatal
ultrasound examination: neural tube defects, Trisomy 21, Trisomy 18 ¢ Foetal or parental exposure to potentially teratogenic, mutagenic, or carcinogenic
agents: drugs, chemicals, radiation, infection ¢ A positive carrier screening test result: cystic fibrosis, thalassemia, sickle cell
anemia, Tay-Sachs etc. ¢ Mother is a known/presumed carrier of an X-linked disorder: Duchenne Muscular
Dystrophy (DMD), hemophilia ¢ Recurrent pregnancy loss (2 or more) or multiple IUFDs (Intrauterine Fetal Demise) ¢ Infertility where either parent is suspected of having a chromosome abnormality or
other genetic factors
Hereditary Cancers ¢ A cancer known to be associated with specific genes or mutations: breast, ovarian,
colorectal ¢ A positive germline mutation revealed by family genetic testing or tumour profiling
testing ¢ A compelling family history of cancer: young age at onset, bilateral lesions, familial
clustering of related tumours
Cardiovascular Genetics ¢ A cardiovascular disorder: cardiomyopathy, long QT, congenital heart defect ¢ A vascular disorder including arterial aneurysms/dissections and connective tissue
disorders: Marfan & Ehlers Danlos syndrome ¢ A high level of lipids (fats, cholesterol, and triglycerides) or lipoproteins circulating
in the blood: hyperlipidemias, familial hypercholesterolemia
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
Rifaat Rawashdeh is a Licensed Certified Genetic Counselor with NRL
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 f