A lot of people are born into wealthy family and they inherit everything  through their ancestry. This might be from father, mother, siblings, grand parents, aunts and uncles. Others acquire fame and position solely because of the titles of their parents , example monarchy and lord ship. On the other hand, bad reputation of parents such as having an alcoholic father, murder convict father does also equally affect the offspring. While most people are aware of the above, not all are familiar with the consequence of born to a parent with familial or inherited diseases.  

We hear others comment on our child as ‘chip of the old block’, which not only cover  physical attributes, but also mannerisms, habits and character. Off springs when fully grown, invariably they get the height ,facial features of their parents in their good or bad attributes. Physical features like  curly hair, baldness, freckles, dimple, hair colour and skin colour are all inherited from one parent or the other.In this  blog, let me address medical aspect of inheriting ancestral traits by enlightening the  diseases transmitted by genes.  

Genetically transmitted diseases are caused by abnormalities or mutations in an individual’s DNA  or chromosomes that are inherited from one or both parents. Genes are a segment of DNA while genomes are the entire genetic material of an organism.Genes are packed in chromosomes. A single gene can contain about 1 million base pairs of DNA and a single chromosome can contain about 1,000 gene  Around 1 in 50 people are affected by known single-gene disorder, while around 1 in 263 are affected by chromosomal disorder. Around 65% of people have some kind of health problem as a result of congenital genetic mutations. We know human beings have 23 pairs of chromosomes in the nucleus of cell. Each chromosome is made up of DNA or deoxy ribonucleic acid . DNA is also found in mitochondria in the cell.   

There are several mechanisms by which these mutations  may be inherited. They are  autosomal dominant inheritance in which inheritance occurs when a single copy of a mutated gene is enough to cause the disease. If the parent has a mutated gene in one of his/her two chromosomes there is a 50% chance that his/her offspring will inherit the disease.An example for autosomal dominant gene is Huntington’s chorea. 

 In Autosomal recessive inheritance, an individual inherits two copies of inherited mutated gene one from each parent. If both parents carry a mutated gene but do not show symptoms of the disease there is a 25% chance of their offspring will inherit two copies the mutated gene and develop the disease. Cystic fibrosis and sickle cell anemia are two examples of autosomal recessive inheritance.  

In X-linked inheritance occurs the mutated gene is located on the X chromosome. Since females have two X chromosomes while males have one X chromosome, one X chromosome of female will not manifest symptoms, while the male offspring having one X chromosome will manifest the disease. Haemophilia and colour blindness are examples of X-linked recessive inheritance.   

Mitochondrial inheritance is more common than previously thought. The DNA in the mitochondria of each cell is inherited from the mother, as the egg provides most of the mitochondria to the developing embryo. If the mother has a mutated mitochondrial DNA, all of her offspring will develop the disease. Type 2 Diabetes and  Friedreich\'s ataxia are examples of diseases transmitted through mitochondrial inheritance.   


Genetically transmitted diseases occur in all systems of human body such as gastr-intestinal system, nervous system, cardiovascular system Skin, genito-urinary system, musculo-skeletal system and special senses. Among them, most known diseases are cancers of breast, prostate, stomach, haemophilia, cystic fibrosis, retinitis pigmentosa, and Down’s syndrome.  These diseases can be identified through gene mapping, which is commercially available now.  

Hypertrophic Cardiomyopathy is the most common genetically transmitted  cardiovascular disease. Cardiomyopathy is a general term for diseases of the heart muscle, where the walls of the heart chambers have become stretched, thickened or stiff. This affects the heart's ability to pump blood around the body.Many cardiac disorders can be inherited, including arrhythmias and congenital heart disease, It has been well established that high blood cholesterol. Coronary artery disease leading to heart attack, stroke, and heart failure can run in families, indicating the risk of  inherited diseases.  

.Neurological Conditions that are inherited are Alzheimer’s Disease.,Huntington\'s Disease,Epilepsy.Parkinson Disease. There  are other inherited diseases such as Leukodystrophies,phenylketonuria,Tay-sachs disease and Wilson’s disease affecting the CNS. Alzheimer\'s disease is a type of progressive dementia which affects people who are over 65 year. First the patient suffers from short term memory loss which deteriorates into confusion and personality change. Huntington's disease is a condition that damages nerve cells in the brain causing them to have involuntary movements and loss of balance. It is inherited if one of the parent carries the mutated gene. The damage to the brain gets worse over time. It can affect movement, cognition (perception, awareness, thinking, judgement) and mental health. Ataxia causes the sufferer to lose balance on walking , unable speak and swallow properly as  the coordination centre in brain is affected.  

Genetically transmitted diseases affectimg gasro-intestinal system include juvenile polyposis, hereditary hemochromatosis, polycystic liver disease, autoimmune hepatitis, Budd-Chiari syndrome, alpha-1-antitrypsin deficiency, and Wilson disease. Other diseases are pancreatitis, celiac sprue, Peutz-Jeghers syndrome, endocrine tumours, hereditary haemorrhagic telangiectasia, and inflammatory bowel disease.  

.Most cancers are not linked to inherited faulty genes. Only around 5% cancer diagnosed ate linked to an inherited faulty genes. Both men and women can have a faulty BRCA1 BRCA2 genes. People who inherit faulty version of these genes have an increased risk of developing different types of cancers. This includes breast cancer, ovarian cancer and prostate cancer. Through genetic mapping, these faulty genes can be identified and if positive, sufferers can cut the risk by undergoing prophylactic removal of breast, ovary or prostate. 

Skin conditions known for genetic transmission include atopic dermatitis, psoriasis, vitiligo, albinism and. epidermolysis bullosa. Most common dysplasias like osteogenesis imperfecta, achondroplasia, and osteopetrosis are genetically transmitted musculo skeletal diseases. In special senses,  night blindness, retinitis pigmentosa and retinoblastoma fall in the category of genetically transmitted diseases. 

For genetically transmissible conditions there are no effective therapy except management of symptoms.But It has been reported that gene therapy has been successfully developed to reverse the progress of retinitis pigmentosa.In order to prevent these genetically transmissible diseases, it is advisable to get gene mapping in order to plan future life accordingly. Also those who are positive for autosomal dominant genetic defect, it is advisable for the sufferers not to have children. In the last century  certain sections of people in European countries advocated eugenics by which procreation by healthy people only was  promoted to suppress the genetically transmissible diseases. This approach was deemed to be morally wrong and did not get popular.

Share On

This blog is about my experience as a doctor working in various countries in different clinical set up. This experience spans through 45 years, in which I acquired a lot of favourable contacts and unfavourable encounters. I shall dig deep into them and make it interesting to the readers. Unlike others in the profession, I worked as a community medical officer in a remote areas, prison medical officer, benefit service medical officer, in cardiac surgery in prestigious institutions and as a private doctor. I was managing my own businesses, and real estate in three continents. I hope the information I impart will be valuable to the like minded readers.

Related Post

Comment Form