x Abu Dhabi, UAEWednesday 26 July 2017

Little-known childhood disorder 'prevalent in the UAE'

Emiratis suffer from some rare genetic disoders at a much higher rate than the general population.

ABU DHABI // A little-known genetic disorder that can stunt children's physical and mental development and often cause them to die young is over three times more prevalent in the UAE than elsewhere, a study suggests.

Lysosomal storage disease occurs when the body lacks the enzymes it needs to break down food and waste products. As a result, toxins accumulate in the body, affecting the nervous system and leading to developmental complications.

With some types of the disease, few sufferers live beyond their teens.

It is passed down through a recessive gene, so if both parents have the defective gene each of their children has a one in four chance of suffering the condition.

Sufferers initially look healthy, but between the ages of one and two they start to develop larger and more prominent eyes, tongues and foreheads.

There are about 50 types of the disease, each affecting a different enzyme. Certain enzymes break down certain chemicals.

The disease varies according to which enzyme is missing or non-functional. Two thirds of the diseases can stunt mental development.

Dr Fatma Al Jasmi, an assistant professor of paediatrics at UAE University and a metabolic consultant at Tawam Hospital, has been studying the prevalence of the disease in the UAE.

Dr Al Jasmi's initial results suggest the rate of certain forms is more than three times higher here than in other countries with the highest incidence rates.

The study examined hospital records starting last year and is continuing without a set end date.

Sanfilippo syndrome affects nearly 1.6 out of 100,000 babies born in the UAE, compared with 0.47 in Australia, the country with the highest observed prevalence.

And with the Emirati population the figures are much higher - about 3.7 for every 100,000 births.

Other forms also show higher rates. Gangliosidosis affects 1.3 out of 100,000 births in the UAE, compared with 0.41 in the Netherlands. For the Emirati population, the number rises to 2.8.

Both disorders are caused by a lack of enzymes needed to break down sugar molecules.

The condition can be treated with injections of the missing enzymes, but these are expensive. The injections, usually given weekly, cost Dh4,000 and Dh5,000 each - more than Dh200,000 a year.

And as their bodies grow children need higher doses to compensate, said Dr Fatma Bastaki, the head of paediatrics at Al Wasl Hospital.

Emiratis are covered by the Government, but most insurance companies do not cover treatment for expatriates with rare genetic diseases, leaving them to rely on charity or return to their home countries.

Another option for severe cases is yearly bone marrow transplants, which are not available in the UAE and can cost the equivalent of Dh1 million.

The keys to preventing the disease, as with other recessive gene disorders in a country where intrafamily marriage is common, are premarital screening, prenatal diagnosis and newborn screening.

While newborn-screening programmes check for some metabolic disorders, they cannot detect all forms. And unless specifically requested, metabolic diseases are not part of the premarital screening programme.

It is possible to check, before they are implanted, whether embryos created by in-vitro fertilisation have two copies of a defective gene, but it costs up to Dh40,000 and is not available in the UAE.

"Many parents go to Saudi Arabia or Jordan for the procedure," said Dr Bastaki. "It's a small price to pay to prevent a lifetime of complications."

mismail@thenational.ae