Having a genetic disorder sounds truly unpleasant but equipping yourself with knowledge can make all the difference in the world.
Nature works in wondrous ways. From our genes that are the fundamental building blocks of our DNA that makes us what we are, to our cells that replicate and make us whole. It seems like a simple, linear process but what if there’s an interruption on the genetic level? This is where a gene becomes defective and this is what causes someone to be born with a genetic disorder.
Not all genetic disorders result in death but there are no known cures. There are many genetic disorders that have been identified and it is possible to get an accurate diagnosis during early childhood. After the diagnosis, parents will be able to make lifestyle adjustments and prepare for the future of their child. The diagnosis can also influence their decision to have more children.
Genetic disorders present differently and can have a variety of outcomes. Read on to find out more about the different types of genetic disorders.
Autosomal dominant disorder
A person with autosomal dominant disorder usually inherits it from one affected parent. Thus, a child with one affected parent has a 50 percent probability of inheriting an autosomal dominant disorder. Examples of this kind of disorder includes Huntington’s disease which affects muscle co-ordination and leads to mental decline and behavioural symptoms, and neurofibromatosis type 1 and type 2 where tumours grow anywhere on the body (type 1) and cranial nerve (type 2).
Autosomal recessive disorders
In cases of autosomal recessive disorders, the affected person has unaffected parents who each carry one copy of the mutated genes. There is a 25 percent probability of inheriting an autosomal recessive disorder from two unaffected people who each have one copy of the mutated gene. Disorders such as albinism where a person either completely or partially doesn’t have pigment in their skin, hair and eyes, and spinal muscular atrophy which is a rare neuromuscular disorder characterised by loss of motor neurons and progressive muscle wasting which could lead to early death.
Thalassemia is an autosomal recessive disorder that is the most common genetic disorder in Malaysia, according to the Journal of Biomedicine and Biotechnology. This condition is where the affected person’s haemoglobin is abnormal which results in impaired transportation of oxygen as well as red blood cell death. Complications include too much iron in the body, bone deformities and and heart problems.
X-linked dominant disorder
An average human has 23 pairs of chromosomes and 1 of those pairs, either XX or XY, denotes the sex of a person. XX points to a female and XY points to a male. An X-linked dominant disorder is caused by a mutation in the genes on the X chromosomes. Males and females are both affected because both have the X chromosome. Rett syndrome and Aicardi syndrome are examples of an X-linked dominant disorder characterised by postnatal neurological disorders and development problems.
An example of an X-linked recessive disorder is haemophilia which is a disorder where the body isn’t able to form blood clots which could cause the affected person to bleed out when a blood vessel is broken. Haemophilia is more likely to occur in males compared to females because while females have two X chromosomes, males only have one. As haemophilia is a recessive disorder, just one mutation is needed to affect males while females are usually asymptomatic (don’t show symptoms) carriers.
Multifactorial genetic disorders
Other than the aforementioned genetic disorders, there are also disorders that don’t really have a clear-cut pattern of inheritance. These are known as multifactorial disorders that are the effects of multiple genes combined with lifestyle and environmental factors. A multifactorial genetic disorder is known to run in families
These disorders include heart disease and diabetes which are caused by an inherited factor and also how a person lives his or her life. With so many factors causing a multifactorial genetic disorder, it is difficult to pinpoint a person’s risk of inheriting or even passing on these disorders.
Multifactorial genetic disorders include asthma, multiple sclerosis (autoimmune disease), certain cancers, cleft palate, hypertension, obesity and infertility.
At this point in time, treatment of genetic disorders is focused on the symptoms rather than the disorder itself. This is to help improve the patient’s quality of life. Gene therapy is a form of treatment where a healthy gene is inserted into an affected person’s genes. It is hoped that gene therapy can help alleviate the symptoms caused by the mutated gene or slow the progression of the disease. Gene therapy is still being researched as a way of treating genetic disorders.
For parents with children who have genetic disorders, know that you’re not alone and there’s support out there for you. There are plenty of online resources along with support groups that can help you care for your child as well recommendations of doctors who can help with symptoms (see sidebar).
Down syndrome (Trisomy 21)
Down syndrome is a genetic disorder caused by a third copy of chromosome 21, hence the name, Trisomy 21. Characteristics of Down syndrome include delay in physical growth, intellectual disability and a facial structure that features a flat nasal bridge, protruding tongue and slanted eyes. Developmental milestones such as crawling and walking is delayed in individuals with Down syndrome.
Parents of the affected individual are usually genetically normal but risk factors of having a baby with Down syndrome include, advanced maternal age (by 35 years old, the risk of having a baby with Down syndrome is about 1 in 350, by 40 years old, 1 in 100) and having previously had a child with Down syndrome. Screening tests are available during pregnancy, to test for Down syndrome.
For more information on Down syndrome, check out the Kiwanis Down Syndrome Foundation at www.kdsf.org.my or contact them at 03-78030179.
How to get help
Here are some helpful resources where you can get help and find out more about genetic disorders:
- Malaysian Rare Disorders Society
A voluntary organisation with the help and guidance of the Genetic Unit, Department of Paediatrics, University Malaya Medical Centre. Check them out at www.mrds.org.my or their Facebook, www.facebook.com/MalaysianRareDisordersSociety
- Thalassaemia Association of Malaysia
www.facebook.com/ThalassaemiaMalaysia or contact them via phone at: 03-40317049
- Yayasan Jantung Malaysia
Information on Inherited Cholesterol Disorder at: www.yjm.org.my. Click on ‘Health Articles’ and look for ‘Inherited Cholesterol Disorder’.
- Hatching Center
For special needs children. The team at the center consists of special education teachers, play therapists, speech pathologists and more. Find them at C-43-3A, Jaya One, Jalan Universiti, 46200 Petaling Jaya, Selangor, Malaysia. Contact them at: 011-11338518 or email them at firstname.lastname@example.org