New UCLA study raises questions about genetic testing of newborns

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New UCLA study raises questions about genetic testing of newborns

http://www.eurekalert.org/pub_releases/2010-12/uoc--nus120310.php

Mandatory genetic screening of newborns for rare diseases is creating unexpected

upheaval for families whose infants test positive for risk factors but show no

immediate signs of the diseases, a new UCLA study warns.

" Although newborn screening undoubtedly saves lives, some families are thrown on

a journey of great uncertainty, " said UCLA sociology professor Stefan

Timmermans, the study's lead author. " Rather than providing clear-cut diagnoses,

screening of an entire population has created ambiguity about whether infants

truly have a disease — and even what the disease is. "

The study, which appears the December issue of the Journal of Health and Social

Behavior, describes these families as " the collateral damage of newborn

screening, " an unanticipated consequence of the expansion of mandatory screening

for a wide range of conditions in 2005.

" Basically you're telling families of a newborn, 'Congratulations, but your

child may have a rare genetic condition. We just don't know, and we don't know

when we'll know,' " Timmermans said.

Conducted with Mara Buchbinder, who earned a doctorate in anthropology at UCLA

and is now an assistant professor of social medicine at the University of North

Carolina–Chapel Hill, the study paints a picture of families caught in limbo as

they wait months for conclusive evidence that their children are out of the

woods for conditions that have been associated with schizophrenia, mental

retardation, heart and lung disease, coma, and sudden death.

In many cases, the medical results never come; the children slowly age out of

having risk factors for up to 29 metabolic, endocrine or hemoglobin conditions.

But by that time, some families are so traumatized that they follow unwarranted

and complicated regimens for years afterward, including waking their children up

in the middle of the night, enforcing restrictive diets and limiting contact

with other people.

" Years after everything appears to be fine, parents are still very worried, "

Timmermans said.

For three years, Timmermans and Buchbinder followed 75 California families whose

newborns received screenings that sent up red flags for diseases chacterized by

an inability to digest food containing fat, proteins or sugars. Of the total, 40

of the infants became what the researchers describe as " patients-in-waiting " —

children who have not developed symptoms but whose genetic tests raise flags.

" The parents don't know whether their child is a false positive or they're a

true positive, " Timmermans said.

In one particularly poignant case of a patient-in-waiting, a father refused to

allow anyone but the infant's mother to care in any way for the boy, fearing

contamination that might aggravate his potential condition. More than a year

after the baby's birth, the mother had not been apart from the baby. Her dream,

she confessed to the researchers, was to be able one day to go on a date with

her husband.

Parents of another patient-in-waiting were afraid to pursue an out-of-state job

opportunity because they were uncertain about the quality of medical care that

would be available for their child with potential medium-chain acyl-coenzyme A

dehydrogenase deficiency (MCADD), a condition that prevents babies from being

able to turn fat into energy. Without treatment, MCADD babies can experience

seizures, extreme sleepiness or comas, and even die. And several parents decided

either to give up a job or not return to a job in the hopes of keeping a closer

eye on their children in case symptoms of the rare diseases did eventually

surface.

" When the test results ultimately suggest the risk is nothing or not as

significant as with patients who are symptomatic, the physicians are ready to

let go of preventative measures, " Timmermans said. " But the parents are

reluctant to give them up because they come to believe that they're keeping

their child disease-free. Over and over again, we saw parents and doctors at

odds. "

The genetic testing of newborns dates back four decades, when the approach

showed promise in identifying phenylketonuria (PKU), a genetic disorder

characterized by the body's inability to utilize an essential amino acid,

phenylalanine. The disorder causes a build-up of phenylalanine in the blood,

which can result in mental retardation, brain damage, seizures and other

problems. But if PKU sufferers are identified early enough, they can avoid these

problems through diet and medication.

The advent of new screening technologies in the late 1990s vastly increased the

number of potential diseases that could be detected with a blood sample easily

obtained by pricking the heel of a newborn. Genetic testing of newborns got

another shot in the arm in 2005 when the American College of Medical Genetics

called for mandatory screening of 29 conditions and 24 sub-conditions. By 2009,

all 50 U.S. states and the District of Columbia screened for at least 21 of the

29 recommended conditions, and the full recommendations had been adopted by 44

states, including California.

Other countries have since adopted genetic screening, but they test for fewer

conditions and add new conditions more slowly than the U.S. The study findings

cast doubt on the medical efficacy of the battery of screenings administered

widely in America, the researchers said.

" Expanded newborn screening has called into question whether screening targets

correspond to actual diseases or just benign forms of human variation, "

Buchbinder said.

" There are many more positive screenings than were anticipated based on the

incidence of the diseases in the general population, " Timmermans added.

Nobody knows the number of families who fall into the patient-in-waiting

category, but it is assumed to be a relatively small number. Still, the number

is much larger than was anticipated when screening for a wide range of

conditions began in 2005, the study argues.

The researchers also suggest the need for increasing the speed with which

follow-up tests are administered so that parents of patients-in-waiting spend

less time wringing their hands.

" When the American College of Medical Genetics advocated for the expansion of

newborn screening, they argued that the societal benefit of newborn screening

would be the avoidance of diagnostic odysseys in which parents of kids with rare

diseases travel from doctor to doctor in an attempt to find out what is wrong

with them, " Timmermans said. " Our study shows that, in fact, the expansion of

newborn screening has created a new population on diagnostic odysseys — the

parents of these patients-in-waiting. Now we need to figure out how to

dramatically shorten or eliminate this unexpected and stressful journey. "