Hereditary Diseases

We inherit our looks and traits from our parents or grandparents. Sometimes, a child turns out to be the spitting image of its mother or father, or a mixture of both, depending on whoever wins the battle of the genes. On the flip side, we also get hereditary diseases from our parents. 

If one or both parents are carriers of a certain type of genetic disorder, it is likely that one or several of their children will be affected, too. A condition such as thalassaemia is an inherited blood disorder that is quite common in Bangladesh. However, detection, prevention and research on hereditary diseases are not that advanced in this developing country of 165 million people.  
People with thalassaemia have little or no haemoglobin, a substance which is used by red blood cells to carry oxygen around the body. Another type of blood-related genetic disorder, haemolytic anaemia, is also found in Bangladesh, according to health experts. 
“Among blood-related genetic disorders, thalassaemia is quite common. We get patients with haemoglobin E-beta thalassaemia. When carriers of this disease marry, there is 25 percent chance that any child born to the couple will get it. Then there is 25 percent chance that the child will be born with immaculate health, and 50 percent chance of the child being a carrier of the faulty gene. Every pregnancy of the carrier couple will have this same risk factor,” Dr M Selimuzzaman, professor of paediatrics at Dhaka Shishu (Children) Hospital, told this correspondent. 
Dr Selimuzzaman said they also get patients with hereditary spherocytosis. “But it is not that common. Hereditary spherocytosis is a condition that affects red blood cells. People with this condition typically experience a shortage of red blood cells, yellowing of the eyes and skin, and an enlarged spleen. The chance of a child of a carrier getting the disease is 50 percent.
Most newborns with hereditary spherocytosis have severe anaemia, although it improves after the first year of life, if proper treatment is carried out.” 
“The same goes for thalassaemia. Bone marrow transplant can be done, but it is an extremely expensive procedure and rarely done in Bangladesh. But the disease can be managed with appropriate treatment. With an extensive action plan and implementation of proper care, a person with thalassaemia can live up to the age of 40-50 years. Bone marrow transplant has many hazards and it is not a prevalent option in this country, so we usually go for managing the complications posed by the disease,” the professor added. 
 Another type of blood-related hereditary disease is glucose-6-phosphate dehydrogenase (G6PD) deficiency. Also known as favism, it is a genetic disorder that occurs mostly in males. In affected individuals, a fault in an enzyme called glucose-6-phosphate dehydrogenase causes red blood cells to break down prematurely. This destruction of red blood cells is called haemolysis. 
“We get patients with haemophilia as well. Haemophilia is caused by an inherited genetic mutation, which mainly affects males. When the DNA sequence that makes up a gene undergoes permanent alteration, some of the body’s processes won’t function in the normal way. Usually, when you cut yourself, substances in the blood known as clotting factors combine with blood cells called platelets to make the blood sticky. This makes the bleeding stop eventually. However, with haemophilia, there aren’t as many clotting factors as there should be in the blood. This means that someone with the condition bleeds for longer than usual. The condition is passed to a child by one or both of their parents,” said Dr Selimuzzaman.
While talking about research conducted on hereditary diseases in Bangladesh, Dr Selimuzzaman said: “A study has been conducted on thalassaemia and 8 to 9 percent of our population is carrier of the disease. If you go to the Chittagong Hill Tracts region, you will find that about 13 percent of the population are carriers. Consanguineous marriages increase the chance of spreading this disease. Data on other diseases are not available for Bangladesh.” 
About research and mapping of hereditary diseases, Dr Reaz Mobarak, head of High Dependency and Isolation Unit at the Department of Epidemiology and Research, Dhaka Shishu Hospital, said: “We get many patients with genetic diseases. What we have identified so far is just the tip of the iceberg. Most genetic diseases go undiagnosed and unidentified in this country. Here, we have been able to identify quite a variation of hereditary diseases, such as Russel-Silver syndrome, ataxia-telangiectasia syndrome, Beckwith-Wiedemann syndrome, Duchenne muscular dystrophy, homocystinuria, incontinentia pigmenti and Dandy-Walker malformation. I see over 100 patients every day, therefore, I was able to discover these conditions. Many neurological patients come to us and from there, we are able to isolate neurometabolic diseases and we document all that we come across.”
 “Bangladesh is a developing country with a huge child population, so we need to identify these hereditary disorders and diseases. This is a social responsibility, not only for the early management of the diseases, but also for counselling. People should be made aware of the risks of consanguineous marriages as they are a primary factor in the spreading of hereditary diseases. Carriers of certain types of diseases should be made aware of the consequences of marrying another carrier and the risk it will pose for their future children,” Dr Mobarak added.
“There is lacking in our healthcare system. Diseases sometimes skip a generation, such as autosomal recessive. This lack of awareness of passing diseases to your progeny is compounding the spread of hereditary diseases. If we cannot protect our next generations, in the future we may have a larger number of children suffering from various types of diseases or disorders.  Many years from now, when we move up to the status of middle or high income country, the types of diseases will also change. Poverty-related diseases and disorders will subside and non-communicable diseases and genetic diseases might be on the rise,” Dr Mobarak said. 
“To my knowledge, we do not have any research on hereditary disorders, other than that of thalassaemia. We have a DNA lab for genetic study where thalassaemia can be identified in a foetus as early as 14 weeks. Testing for genetic diseases is expensive and we do not have many specialised laboratories for that. We can do testing for chromosomal disorders, but you have to wait for months to do that at BIRDEM (Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders). What I want to point out is that we need specialised labs for identifying genetic diseases; we need the expertise, specialised geneticists, and adequate funding as it is a comprehensive area of study and very time consuming. This is a very expensive field of research and testing kits are also very expensive,” Dr Mobarak added.
Bronchial asthma is a common condition among children these days and it is considered as a hereditary disease. Cystic fibrosis (CF) is also a genetic disease, which is rare but is now being found in Bangladesh. It is a progressive disease that causes persistent lung infections and limits the ability to breathe over time. In people with CF, a defective gene causes a thick, build-up of mucus in the lungs, pancreas and other organs. 
To learn about breathing-related hereditary disorders, this correspondent talked to Dr Jotsna Ara Begum, a pulmonologist at Dhaka Shishu Hospital.  “Bronchial asthma is a multi-factorial disease. If a parent had asthma as a child or is still asthmatic, there is a chance that the child will inherit it. But trigger factors also play a role in bronchial asthma, it is not purely genetic. House dust, cockroaches or pollen and other environmental factors also exacerbate asthma.” 
“Cystic fibrosis is a lung disease, but it is not so common in Bangladesh. It is a disease of developed countries, but we are now getting a few patients here with this condition. It is just on the rise. We cannot do mutation analysis, so we determine the condition with few other tests. There are scattered studies about its presentation, but no wide-ranging study has been done about the disease in Bangladesh. When a patient comes with recurring respiratory infection, we consider other aspects and try identifying its etiology. We do a sweat test and come to the conclusion whether the patient has the disease. But till now, we are conducting tests that were done 40 years ago, we do not have proper provisions for testing of cystic fibrosis,” the doctor added. 
About hereditary neurological disorders, Dr Mustafa Mahbub, associate professor and consultant at the Paediatric Neuroscience Department of Dhaka Shishu Hospital said: “Among neuromuscular disorders, Duchenne muscular dystrophy (DMD) is most common. It is a genetic disorder characterised by progressive muscle degeneration and weakness. Then there is Becker muscular dystrophy (BMD). It is also a muscular dystrophy, a genetic, degenerative disease primarily affecting voluntary muscles. BMD is similar to DMD, but allows the voluntary muscles to function better than they do in DMD. The heart muscle, however, can be affected similarly to the way it is with DMD. We also get patients with spinal muscular atrophy (SMA). It is a genetic disease that is not that common, it affects the part of the nervous system that controls voluntary muscle movement. Most of the nerve cells that control muscles are located in the spinal cord, which accounts for the word spinal in the name of the disease. SMA is muscular because its primary effect is on muscles, which don’t receive signals from the nerve cells.”
“Then we have hereditary spastic paraplegia. This is a broad term for a group of rare inherited disorders that cause weakness and stiffness in the leg muscles. Gradually, the symptoms get worse over time. We also get patients with MPS I (mucopolysaccharidosis I). It is a condition that affects numerous parts of the body. It is an increasingly debilitating disorder. However, the rate of progression varies among affected individuals. MPS I is caused by mutations in the IDUA gene. And there are a few others. We try to administer supportive treatment for most of these conditions. We do not have the means for testing these diseases, so we send them (patients) to India. The patients we get here are mostly from lower income families and they can hardly afford these tests,” Dr Mahbub added. 

Photos: Internet.

Hereditary Diseases

We inherit our looks and traits from our parents or grandparents. Sometimes, a child turns out to be the spitting image of its mother or father, or a mixture of both, depending on whoever wins the battle of the genes. On the flip side, we also get hereditary diseases from our parents. If one or both parents are carriers of a certain type of genetic disorder, it is likely that one or several of their children will be affected, too. A condition such as thalassaemia is an inherited blood disorder that is quite common in Bangladesh. However, detection, prevention and research on hereditary diseases are not that advanced in this developing country of 165 million people. People with thalassaemia have little or no haemoglobin, a substance which is used by red blood cells to carry oxygen around the body. Another type of blood-related genetic disorder, haemolytic anaemia, is also found in Bangladesh, according to health experts. Among blood-related genetic disorders, thalassaemia is quite common. We get patients with haemoglobin E-beta thalassaemia. When carriers of this disease marry, there is 25 percent chance that any child born to the couple will get it. Then there is 25 percent chance that the child will be born with immaculate health, and 50 percent chance of the child being a carrier of the faulty gene. Every pregnancy of the carrier couple will have this same risk factor, Dr M Selimuzzaman, professor of paediatrics at Dhaka Shishu (Children) Hospital, told this correspondent. Dr Selimuzzaman said they also get patients with hereditary spherocytosis. But it is not that common. Hereditary spherocytosis is a condition that affects red blood cells. People with this condition typically experience a shortage of red blood cells, yellowing of the eyes and skin, and an enlarged spleen. The chance of a child of a carrier getting the disease is 50 percent. Most newborns with hereditary spherocytosis have severe anaemia, although it improves after the first year of life, if proper treatment is carried out. The same goes for thalassaemia. Bone marrow transplant can be done, but it is an extremely expensive procedure and rarely done in Bangladesh. But the disease can be managed with appropriate treatment. With an extensive action plan and implementation of proper care, a person with thalassaemia can live up to the age of 40-50 years. Bone marrow transplant has many hazards and it is not a prevalent option in this country, so we usually go for managing the complications posed by the disease, the professor added. Another type of blood-related hereditary disease is glucose-6-phosphate dehydrogenase (G6PD) deficiency. Also known as favism, it is a genetic disorder that occurs mostly in males. In affected individuals, a fault in an enzyme called glucose-6-phosphate dehydrogenase causes red blood cells to break down prematurely. This destruction of red blood cells is called haemolysis. We get patients with haemophilia as well. Haemophilia is caused by an inherited genetic mutation, which mainly affects males. When the DNA sequence that makes up a gene undergoes permanent alteration, some of the bodys processes wont function in the normal way. Usually, when you cut yourself, substances in the blood known as clotting factors combine with blood cells called platelets to make the blood sticky. This makes the bleeding stop eventually. However, with haemophilia, there arent as many clotting factors as there should be in the blood. This means that someone with the condition bleeds for longer than usual. The condition is passed to a child by one or both of their parents, said Dr Selimuzzaman. While talking about research conducted on hereditary diseases in Bangladesh, Dr Selimuzzaman said: A study has been conducted on thalassaemia and 8 to 9 percent of our population is carrier of the disease. If you go to the Chittagong Hill Tracts region, you will find that about 13 percent of the population are carriers. Consanguineous marriages increase the chance of spreading this disease. Data on other diseases are not available for Bangladesh. About research and mapping of hereditary diseases, Dr Reaz Mobarak, head of High Dependency and Isolation Unit at the Department of Epidemiology and Research, Dhaka Shishu Hospital, said: We get many patients with genetic diseases. What we have identified so far is just the tip of the iceberg. Most genetic diseases go undiagnosed and unidentified in this country. Here, we have been able to identify quite a variation of hereditary diseases, such as Russel-Silver syndrome, ataxia-telangiectasia syndrome, Beckwith-Wiedemann syndrome, Duchenne muscular dystrophy, homocystinuria, incontinentia pigmenti and Dandy-Walker malformation. I see over 100 patients every day, therefore, I was able to discover these conditions. Many neurological patients come to us and from there, we are able to isolate neurometabolic diseases and we document all that we come across. Bangladesh is a developing country with a huge child population, so we need to identify these hereditary disorders and diseases. This is a social responsibility, not only for the early management of the diseases, but also for counselling. People should be made aware of the risks of consanguineous marriages as they are a primary factor in the spreading of hereditary diseases. Carriers of certain types of diseases should be made aware of the consequences of marrying another carrier and the risk it will pose for their future children, Dr Mobarak added. There is lacking in our healthcare system. Diseases sometimes skip a generation, such as autosomal recessive. This lack of awareness of passing diseases to your progeny is compounding the spread of hereditary diseases. If we cannot protect our next generations, in the future we may have a larger number of children suffering from various types of diseases or disorders. Many years from now, when we move up to the status of middle or high income country, the types of diseases will also change. Poverty-related diseases and disorders will subside and non-communicable diseases and genetic diseases might be on the rise, Dr Mobarak said. To my knowledge, we do not have any research on hereditary disorders, other than that of thalassaemia. We have a DNA lab for genetic study where thalassaemia can be identified in a foetus as early as 14 weeks. Testing for genetic diseases is expensive and we do not have many specialised laboratories for that. We can do testing for chromosomal disorders, but you have to wait for months to do that at BIRDEM (Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders). What I want to point out is that we need specialised labs for identifying genetic diseases; we need the expertise, specialised geneticists, and adequate funding as it is a comprehensive area of study and very time consuming. This is a very expensive field of research and testing kits are also very expensive, Dr Mobarak added. Bronchial asthma is a common condition among children these days and it is considered as a hereditary disease. Cystic fibrosis (CF) is also a genetic disease, which is rare but is now being found in Bangladesh. It is a progressive disease that causes persistent lung infections and limits the ability to breathe over time. In people with CF, a defective gene causes a thick, build-up of mucus in the lungs, pancreas and other organs. To learn about breathing-related hereditary disorders, this correspondent talked to Dr Jotsna Ara Begum, a pulmonologist at Dhaka Shishu Hospital. Bronchial asthma is a multi-factorial disease. If a parent had asthma as a child or is still asthmatic, there is a chance that the child will inherit it. But trigger factors also play a role in bronchial asthma, it is not purely genetic. House dust, cockroaches or pollen and other environmental factors also exacerbate asthma. Cystic fibrosis is a lung disease, but it is not so common in Bangladesh. It is a disease of developed countries, but we are now getting a few patients here with this condition. It is just on the rise. We cannot do mutation analysis, so we determine the condition with few other tests. There are scattered studies about its presentation, but no wide-ranging study has been done about the disease in Bangladesh. When a patient comes with recurring respiratory infection, we consider other aspects and try identifying its etiology. We do a sweat test and come to the conclusion whether the patient has the disease. But till now, we are conducting tests that were done 40 years ago, we do not have proper provisions for testing of cystic fibrosis, the doctor added. About hereditary neurological disorders, Dr Mustafa Mahbub, associate professor and consultant at the Paediatric Neuroscience Department of Dhaka Shishu Hospital said: Among neuromuscular disorders, Duchenne muscular dystrophy (DMD) is most common. It is a genetic disorder characterised by progressive muscle degeneration and weakness. Then there is Becker muscular dystrophy (BMD). It is also a muscular dystrophy, a genetic, degenerative disease primarily affecting voluntary muscles. BMD is similar to DMD, but allows the voluntary muscles to function better than they do in DMD. The heart muscle, however, can be affected similarly to the way it is with DMD. We also get patients with spinal muscular atrophy (SMA). It is a genetic disease that is not that common, it affects the part of the nervous system that controls voluntary muscle movement. Most of the nerve cells that control muscles are located in the spinal cord, which accounts for the word spinal in the name of the disease. SMA is muscular because its primary effect is on muscles, which dont receive signals from the nerve cells. Then we have hereditary spastic paraplegia. This is a broad term for a group of rare inherited disorders that cause weakness and stiffness in the leg muscles. Gradually, the symptoms get worse over time. We also get patients with MPS I (mucopolysaccharidosis I). It is a condition that affects numerous parts of the body. It is an increasingly debilitating disorder. However, the rate of progression varies among affected individuals. MPS I is caused by mutations in the IDUA gene. And there are a few others. We try to administer supportive treatment for most of these conditions. We do not have the means for testing these diseases, so we send them (patients) to India. The patients we get here are mostly from lower income families and they can hardly afford these tests, Dr Mahbub added. Photos: Internet.