Mysterious Ailments May Be The Result Of Undiagnosed Genetic Defects

Main Category: Pediatrics / Children's Health
Also Included In: Genetics
Article Date: 05 Jun 2009 - 5:00 PST

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One in every 3,000 babies is born with an inborn error of metabolism -- a genetic defect that interferes with their ability to process substances like carbohydrates, proteins and fats. Until recently, tests to detect many of these very rare, disabling, and sometimes fatal disorders like fatty acid oxidation disorders were rarely used. If the child died, the cause would be listed as unknown or Sudden Infant Death Syndrome (SIDS). If they survived, they would experience a range of symptoms and medical problems throughout their lives such as delays in development, seizures, difficulty with growth and autistic behavior.

New state-mandated screening tests for newborns and the availability of specialized medical centers have improved the timely detection and treatment of metabolic disorders. The Biochemical Genetics Program at NewYork-Presbyterian Morgan Stanley Children's Hospital -- one of only a few specialized programs in New York state -- offers a complete diagnostic and treatment center.

"Early and accurate diagnosis and detection is an essential first step for appropriate management and treatment of patients with these defects, giving them the opportunity to build healthy lives, improve their quality of life, and minimize the burden of their disease," says Dr. Wendy Chung, director of Clinical Genetics at NewYork-Presbyterian Morgan Stanley Children's Hospital and the Herbert Irving Assistant Professor of Pediatrics in Medicine at Columbia University College of Physicians and Surgeons.

Following a multidisciplinary approach, the Biochemical Genetics Program specialists provide treatment specific to patients' metabolic condition. This may include dietary management with a metabolic nutritionist, enzyme replacement therapy and, in advanced cases, transplantation for bone marrow, liver, kidney or heart.

"Our program offers enrollment in cutting-edge clinical trials and research studies for many of these rare disorders," says Dr. Chung. "Reproductive planning is also available, ensuring patients with metabolic disorders, or parents of a child with a disorder, that they will have healthy children."

The program has been bolstered with the recruitment of Dr. Maryam Banikazemi, internationally recognized for her work in the field of lysosomal storage disorders. Dr. Banikazemi is a pediatrician at NewYork-Presbyterian Morgan Stanley Children's Hospital and assistant professor of clinical pediatrics at Columbia University College of Physicians and Surgeons.

The team includes a metabolic nurse, registered dietitian, social worker and genetic counselor. Other specialists include gastroenterologists, cardiologists, neurologists, orthopedic surgeons, ophthalmologists, pulmonologists and transplant surgeons.

In addition to diagnosing and treating children, the Biochemical Genetics Program is available to adults. "We see adults with mysterious ailments; liver failure, hypoglycemia, even symptoms like persistent carpal tunnel syndrome can be a sign of a metabolic disorder," says Dr. Chung, who notes that adult patients commonly are misdiagnosed and treated for other conditions.

Inborn Errors of Metabolism

Inborn errors of metabolism, also known as congenital metabolic diseases or metabolic disorders, are usually due to defects of single genes that code for enzymes that break down and build chemicals in the body. In most of the disorders, problems arise due to accumulation of chemicals which are toxic or interfere with normal function, or to a deficiency in essential chemicals. The earliest screening for a congenital metabolic disease, phenylketonuria (PKU), was pioneered in the late 1960s, and involves using blood samples on filter paper obtained by pricking a newborn baby's heel on the second day of life. This PKU test is still in use today. Congenital hypothyroidism was the second disease widely tested in the 1970s. The development of tandem mass spectrometry screening in the early 1990s led to a large expansion of potentially detectable congenital metabolic diseases. Additional tests have been added to many screening programs over the last decade. Newborn screening has been adopted by most countries around the world, though the lists of screened diseases vary widely.

Sources
NewYork-Presbyterian Morgan Stanley Children's Hospital and Columbia University Medical Center