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5 Things to Know About Rare Metabolic Diseases

Published on Feb. 27, 2023

An estimated 300 million people worldwide live with a rare disease and of this group, 72% are due to genetics. This means that in most cases, one may inherit a rare condition for no particular reason other than it is just part of their genetic makeup. Our genes (or genotype) come in two sets – one from mom, the other from dad – and they are made of DNA. Strands of DNA make up our chromosomes, which determine our physical features, like hair and eye color, and our biological features, such as our blood type.

In some extremely rare cases, an inborn error of metabolism can occur in one’s genes, meaning that the body cannot turn food into energy due to its inability to properly break down (or metabolize) food. This is known as a metabolic disorder, and here are five things to know about them:

  1. Many rare metabolic diseases can be detected at birth. The California Newborn Screening Program tests all babies born in California for 80 different disorders, many of which are genetic, including some of the most common metabolic diseases. Parents may recall this testing, which takes place in the hospital after their baby is born. To administer the test, a care provider pricks your baby’s heel and takes a few blood drops as samples. The blood samples are then screened for the 80 different disorders the Newborn Screening Program can detect. In the rare case that a metabolic disease is detected, Valley Children’s Healthcare is 1 of 12 metabolic centers in the state that can diagnose, manage and treat these patients.
  2. As a whole, inborn errors of metabolism occur in 1 in 2500 births. These rare diseases are typically autosomal recessive, which means both mom and dad are carriers of the disorder.
  3. Dietary restrictions will help a metabolic condition. Since a metabolism disorder is the result of the body’s inability to properly turn food into energy, treatment will likely consist of a lifelong dietary restriction. Some of the disorders, like phenylketonuria (or PKU), will require a low protein diet, with low protein medical foods and metabolic formula. Patients will work closely with a metabolic dietitian to monitor the effectiveness of dietary restrictions, growth trends and laboratory tests for needed dietary changes.   
  4. Care will be lifelong. There are professionals who can help you along the way. Each is specially trained to help anyone living with a rare metabolic disease.
  5. Your diagnosis can help your relatives and loved ones. Since in most cases, a metabolic disorder is genetic, that means someone related to you may also be a carrier. A genetic counselor can help with further testing, interpret results and help you understand how it can affect other family members. It is important to trust your care teams because they are there to support you through life’s milestones, from infancy and adolescence to adulthood and family planning. 

by Ann-Marie Roberts, RD, CNSC, Valley Children’s Metabolic Dietitian/NICU Dietitian 

About Valley Children's Medical Genetics and Metabolism Team

The Medical Genetics and Metabolism department offers comprehensive services to children with suspected genetic conditions and uses the latest and most innovative testing and treatments available. Our team includes board-certified and board-eligible physician geneticists, licensed and certified genetic counselors, and nurse coordinators, as well as a metabolic dietitian and social worker. We are certified as a California Children’s Services (CCS) Metabolic Treatment Center for the California Newborn Screening Program and have collaborated with peers in the state and across the nation to pioneer pilot programs that will impact the future of medicine.