Some friends of mine recently had a baby who was diagnosed with Propionic Acidemia. Apparently this means that the baby cannot digest protein. The parents have talked with the doctors extensively about what they can do to help at home, life expectancy, etc., but they are consistently told that all cases are different and there's no way to know what to do. Apparently it comes from a mutated (or recessive maybe?) gene that has to exist in both parents for the disease to appear in the child. I don't think children with this disease live very long, nor do they develop mentally like healthy children. I think the oldest living person with the disease is 18. Any help you might provide would be greatly appreciated.Thanks in advance for your time.

Propionic acidemia can be a devastating condition, but with careful treatment it is sometimes possible for people with the disease not only to reach adulthood successfully but even to get pregnant and deliver healthy babies!

But for parents whose children have propionic acidemia, the first weeks after the symptoms appear seem like a surreal nightmare. Rather than little bundles of joy, or fussy bundles of colic, these children are floppy and weak. Most often the children get increasingly lethargic and don't have those wonderful, quiet, alert moments where baby and parent can connect. Not even feeding is a comfort, with vomiting and poor growth being common features. Often no one knows what the problem is, but without quick intervention, the situation can deteriorate quickly to seizures, coma, and death.

And when the diagnosis is finally made, the situation can sound even more bleak than the previous fears of the unknown. A nightmare indeed!

But a new treatment on the horizon may turn out to be a dream come true.

Propionic acidemia is what we call an inborn error of metabolism. Our bodies use detailed blueprints (our genes) to guide the manufacture of the proteins and enzymes we need to carry out the processes of life. Errors in these genes can lead either to a lack of necessary proteins or to the accumulation of toxic substances.

Most mutations in these genes cause no problem; they are just differences that set individuals apart. But more than 100 known single-gene changes do produce disease. Each of these inborn errors of metabolism is rare, but taken as a group, the conditions are fairly common. They range from very mild to quite severe. Even some of the worst can be successfully treated with something as simple as a dietary change. Others are relentlessly fatal.

Some of my most heart-rending experiences as a physician and as a friend have been watching the devastation caused by inborn errors of metabolism.

Inborn errors of metabolism should be suspected (and often aren't) in any child with persistent vomiting, failure to thrive, lethargy, abnormal muscle function or tone, unexplained seizures, neurological deterioration, or developmental regression-especially in the absence of obvious congenital anomalies. A family history of a similar condition, a peculiar odor, or physical changes such as a large liver or spleen should also lead one to consider inborn errors.

Propionic acidemia is an error in protein metabolism. Every time we eat food that contains protein, our bodies use a series of enzymes to break those huge foreign protein molecules into small pieces. These then become the building blocks we reassemble to form the specific human proteins we need.

In people with propionic acidemia, there is an insufficient supply of one of these enzymes (propionyl coenzyme A [CoA] carboxylase). Without the propionyl CoA carboxylase, there is a bottleneck in protein processing. Propionic acid builds up in the blood. This is known to damage the lining of small blood vessels, allowing the propionic acid to leak into the brain and nerve tissues, where it alters behavior and development.