The Need for Pre-marital Tests

Thousands of infants are born each year with beta-thalassemia. A fairly common blood disorder worldwide, this occurs most frequently in people from Mediterranean countries. 

In an effort to decrease the incidence of genetic diseases in the Kingdom of Bahrain, a premarital screening programme was introduced in 1985. This involved a national campaign to increase the awareness of genetic blood diseases amid the population.

In 1992, the premarital counselling service was extended to include all health centres. When 60,000 11th grade students were screened between 1999 and 2008, the mean prevalence of beta-thalassemia carriers and major were 2,097 (3.5 percent) and 19 (0.032 percent) respectively.

Laying down the law
Beta-thalassemias are inherited in an autosomal recessive manner. At conception, each sibling of an affected individual has a 25 percent chance of being affected, a 50 percent chance of being an asymptomatic carrier, and a 25 percent chance of being unaffected and not a carrier.

In 2004, a law had been passed by the government, which requires all Bahraini couples to undergo mandatory premarital counselling. The development of this law included wide consultation ensuring that socio-cultural customs, theological issues and aspects of human rights had been comprehensively considered.

Financed by the national budget, the national newborn screening (NBS) programme for inherited blood diseases was started in 2007. According to this programme, the cord blood of infants is collected at birth and posted to the central laboratory for testing. The urgency of this procedure is due to the fact that early identification is particularly crucial. Timely intervention can significantly reduce morbidity and mortality.

What can be done
Clinical presentation of thalassemia major occurs between six and 24 months. Affected infants fail to thrive and become progressively pale. Feeding problems, diarrhoea, irritability, recurrent bouts of fever and progressive enlargement of the abdomen, caused by an enlarged spleen, may occur.

If the diagnosis of thalassemia major is established at this stage and if a regular transfusion programme is initiated, growth and development can be normal until 10 to 11 years. Regular transfusions correct the anaemia, suppress erythropoiesis and inhibit increased gastrointestinal absorption of iron.

The after-effects
After age 10 and 11, affected individuals are at a risk of developing severe complications related to iron overload, depending on their compliance with chelation therapy. Complications of iron overload in children include growth retardation and failure of sexual maturation. Adults will face problems involving the heart, liver and endocrine glands.

Iron overload is primarily caused by transfusions. Other complications are hypersplenism, chronic hepatitis B and/or hepatitis C, cirrhosis, HIV infection, venous thrombosis and osteoporosis. The risk for liver cancer is amplified in addition to liver viral infection. In fact, cardiac complications are reported to cause 71 percent of the deaths in individuals with beta-thalassemia major.

Alternative treatments
The only available ultimate cures are bone marrow transplantation (BMT) from a matched family or unrelated donor and cord blood transplantation from a related donor. The aftermath of BMT is related to the pre-transplantation clinical conditions. These include the presence of liver enlargement, extent of liver fibrosis and magnitude of iron accumulation.

In children who lack the above risk factors, disease-free survival is over 90 percent. Prenatal identification of human leukocyte antigen (HLA) compatibility between an affected child and an unaffected foetus allows collection of placental blood at delivery and the option of cord blood transplantation to cure the affected child.

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