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The future in a drop

Blood test allows identification and early treatment of a genetic disorder that leads to brain damage

US AIR FORCE/SGT ERIC T. SHELLERPediatrician José Simon Camelo Junior has a strong argument to convince Brazil’s health authorities to include the exam which identifies galactosemy in the screening of newborn babies. Galactosemy is a genetic disorder that affects an individual’s capacity to metabolize galactose, a sugar that is typical to milk. Health care is not the only reason for such screening. There is also an economic reason. Screening the 600 thousand babies born every year in the State of São Paulo – and providing the ones with this disorder with early treatment – is 33% less expensive than dealing with the health problems that 17 children from this group, in whom galactosemy was identified too late, will develop throughout their lifetime, such as cataracts, liver damage and brain damage.

It took five years of work before the pediatrician from the University of São Paulo in Ribeirão Preto/USP-RP and his team were able to prove that including the galactosemy detection test in newborn screening was also an advantage from the economic point of view. Before doing so, however, they had to get very basic information on this disorder, namely, the number of cases each year in the State of São Paulo, data which had previously been estimated on the basis of screenings made abroad.

During the first and most labor-intensive phase of the research work, the groups from Ribeirão Preto and from three other newborn screening centers analyzed the blood samples of 59,953 babies born in 2006, which is equivalent to 10% of the births registered per year in São Paulo State. The initial survey indicated that 158 newborns possibly had galactosemy. A more specific exam, however, detected that of these 158 babies only three actually suffered from this disorder – and needed urgent treatment. This proportion indicates that approximately one out of every 19 thousand babies born in the state are born with one of the genetic alterations associated with galactosemy, which corresponds to approximately 30 new cases per year in the State of São Paulo. This is a relatively low proportion, but higher than had been imagined.

“The incidence of this disorder in the State of São Paulo is much higher than in the United States or in various European countries, and is almost as high as that in South Africa,” says Camelo Junior, a member of the team led by pediatricians Lea Zanini Maciel, Maria Inez Fernandes and Salim Jorge, from USP-RP. In the United States, one out of every 30 thousand or one out of every 40 thousand babies are born with galactosemy, while in England this proportion is one out of every 60 thousand and in South Africa it is one in every 14 thousand.

Individuals with galactosemy have one of the 230 alterations already identified in the two copies of the gene responsible for the production of the Galt (galactose-1-phosphate-uridyl transferase) enzyme. This enzyme transforms galactose – the main sugar in milk – into glucose, another sugar used by cells as a source of energy. The production of defective or of low quantities of Galt enzymes leads to an accumulation of galactose in the blood and tissues. In high concentrations, galactose generates toxic compounds that affect the liver, causing cirrhosis and a clouding that develops in the crystalline lens of the eyes, provoking a cataract. Other more serious complications arise. As the galactose is not converted into glucose, the levels of this sugar in the blood drop drastically. With less glucose and under the effects of toxic compounds, the brain cells start to die, leading to brain damage.

The undesired consequences of this disorder, which are expensive for the public health system and affect the quality of life of the children and their families, can be easily avoided or minimized, provided that galactosemy is identified immediately after birth. “It is enough to substitute breast feeding with galactose-free milk, such as soy milk, and avoid the consumption of foods that contain galactose during lifetime,” explains pediatrician Gilda Porta, from USP’s Instituto da Criança children’s institute, who has kept track of this disorder for 35 years.

In view of the possibility of this simple and inexpensive intervention – a can of soy milk costs approximately R$ 30, whereas the milk fed to children with phenylketonuria costs nearly R$ 300 -, in the last few years, Camelo Junior has battled for the inclusion of the galactosemy detection test in the Guthrie test performed under the Sistema Único de Saúde/SUS, Brazil’s National Health Care system. At present, the Guthrie test, performed free of charge on newborn infants since 2001, is performed to detect three disorders: phenylketonuria, congenital hypothyroidism and hemoglobinopathy. Three states (Paraná, Santa Catarina and Minas Gerais) also perform the test to detect cystic fibrosis, a disorder that reduces the hydration of the mucosa and other secretions, affecting the digestive and respiratory systems. “Our data shows that in São Paulo galactosemy is as frequent as phenylketonuria, which affects one out of every 19 thousand newborns,” says Camelo Junior, comparing his data with that of the team led by Lea Zanini Maciel.

After establishing the incidence of galactosemy, the pediatrician from Ribeirão Preto decided to verify how much it would cost the State to pay for the galactosemy detection test. With the help of Jair Santos, from the social medicine department, and Alceu Camargo Junior and Cláudia Passador, from the School of Business and Economics of USP-RP, Camelo Junior calculated the expenses related to the galactosemy detection test – the cost of the diagnosis kit, of the transportation to the test center, the telephone contacts and the parents’ time away from work. He also added up the expenses resulting from the late detection of the disorder – outpatient treatment costs, and the cost of hospital stays in intensive care units, expenses with surgery and medication, and the costs of maintaining hospital facilities – he based his calculations on data collected in the course of 20 years of seeing patients at different units of the Hospital das Clínicas teaching hospital at USP-RP’s Medical School.

When adding up the expenses, the screening of the newborns amounted to R$ 937,3 thousand, minus annual interest rate. The early detection of the disorder would prevent the 17 children with the form of galactosemy with the worst prognosis from having to go through chronic treatment and would allow them to lead productive lives. In summary, the public health system would save R$ 1,245 million, the researchers wrote in two papers – one of which was published in the Journal of Inherited Metabolic Disease. “Detecting the disorder in the first seven days after birth is 33% less expensive than treating it later on,” says Camelo Junior, who is currently working to show this data to public health authorities. “I will not stop until they get this data.”

According to the pediatrician, these results represent only part of the work that needs to be done to verify how frequently this disorder occurs in the country. “Other states should conduct similar research studies, because the proportion observed in São Paulo cannot be extrapolated,” he says. The genetic defects associated with galactosemy are more common in Afro descendants than in European descendants. This is why it is likely that the incidence of the disorder is higher in the State of Bahia, for example, then in the South of Brazil.

The project
Pilot study for the introduction of galactosemy detection screening in the State of São Paulo (nº 04/08719-5); Modality Regular Research Awards; Coordinator José Simon Camelo Junior – USP-RP; Investment R$ 118.705,92