New Delhi, April 17 : Gene therapy offers hope of a cure to people with haemophilia, a hereditary blood disorder, where a person is born without one clotting factor in the blood, required for forming a blood clot, said doctors on World Haemophilia Day on Wednesday.

World Haemophilia Day is observed every year on April 17 to raise awareness of the debilitating blood disorder, caused by missing or defective factor VIII (FVIII), a clotting protein.

Because patients with haemophilia are unable to form a strong blood clot after injuries, they continue to bleed, raising the risk of death in severe cases. Even with a minor bleeding episode, haemophilia patients run the risk of joint damage, which can later lead to crippling and other issues.

"The inherited disorder stems from a deficiency or dysfunction in clotting factors crucial for coagulation, primarily factor VIII in haemophilia A and factor IX in haemophilia B. It's inherited in an X-linked recessive pattern, explaining its prevalence in males. Females can be carriers or experience milder symptoms due to their two X chromosomes," Tanmay Deshpande, Consultant General Paediatrics and Paediatric Genetics and Metabolic Diseases, Sir HN Reliance Foundation Hospital, told IANS.

Hence, understanding the genetic basis is vital for affected individuals and healthcare providers. Genetic counselling can help assess inheritance risk and inform reproductive decisions, the doctor said.

According to data from Haemophilia & Health Collective of North (HHCN), India is home to an estimated 1,36,000 people living with haemophilia A -- the second largest globally. Of these, only 21,000 are registered at present.

About 80 per cent of haemophilia cases go undiagnosed in India as several hospitals and medical institutions lack screening capabilities for blood clotting, affecting the diagnosis of new cases.

"In the realm of haemophilia treatment, gene therapy emerges as a tool with transformative potential," Tanmay said.

He explained that the therapy involves the precise delivery of functional genes to correct the underlying genetic defect responsible for deficient clotting factor production in patients

"With the help of viral vectors or other delivery systems, gene therapy aims to restore physiological balance and enable sustained production of clotting factors within the body," he added.

Recent clinical trials display encouraging outcomes, highlighting both the safety and efficacy of this approach. This includes the human clinical trial at the Christian Medical College (CMC) Vellore, a first for India.

Scientists at the CMC deployed a novel technology of using a lentiviral vector to express a FVIII transgene in the patient's haematopoietic stem cell which will then express FVIII from specific differentiated blood cells.

Currently, haemophilia can only be defeated by factor VIII infusions. Complications can be prevented if there is preventative administration of factor VIII, which is unfortunately very expensive for low and middle-income countries. However, gene therapy may help cure the disease.

"Gene therapy is a potentially curative treatment for haemophilia. It uses an adenovirus vector where the defective gene of a haemophilia patient is replaced by a functional gene. This treatment is not yet available in routine clinical practice even in Western countries," Anoop P, Sr. Consultant - Haematology, Aster RV Hospital, told IANS.

"Gene therapy enables editing the faulty gene of a baby, while inside the uterus, who is known to be born with haemophilia, because of strong family history," he added.

With ongoing research diving deep into optimisation and long-term effects, gene therapy promises a paradigm shift in the management and potentially the cure of haemophilia, the doctors said.

/IANS