Ruled Out: Neurotransmitter Disease & More

I'd like to start with an important tip for any patient or parent thereof: be aware of your lab work. It is vital to know the following about labs:

1. When is the sample collected? (This is frequently used in the identifier like: 4/20/09 AFP.)
   
2. When is the sample sent out? (Many labs can't send out after 3PM so it may be next day.)
3. When is the sample received? (Usually the day after it is *sent*, but not always. Fresh samples may have to get there within 2 hours otherwise it is void. Other things, such as clotting and contamination can also void the test--and they won't always tell you!)
4. What is the substance? (plasma, red blood cells, white blood cells, cerebrospinal fluid, urine, tissue, etc.)
5. What lab is it being sent to? (Essential for follow-up. Don't trust your send-out lab.)
   
6. What is the turnaround time? (If weeks, do they count business days only? 2 weeks may actually mean closer to 20 days.)

This may sound anal-retentive to a lot of people out there. But, when it's your kid's life on the line, it is not. When a child has an approximately five-year life expectancy, even a few days delay is intolerable. I can't even tell you how many times (safely 10+ times) this knowledge about Bertrand's labs has shaved days or, such as today, weeks of uncertainty in B's case.

Today, after our Primary Childrens Medical Center lab said to give results a few more weeks, I followed up with Medical Neurogenetics, Inc., the Atlanta based laboratory running the neurotransmitter metabolites panel for Bertrand. Turns out that they had already faxed the results back LAST WEEK. The paper was just sitting in a pile somewhere at PCMC waiting to be scanned in--which can take weeks. So, I had the results faxed directly to Dr. Longo.

Dr. Longo being the fabulous clinician (AND researcher) that he is, and in spite of being out of town at a conference, let me know within minutes that the result was normal and that Bertrand's purine panel returned normal again as well. He is now thinking about next steps. (I call Bertrand my man of mystery!) But, the normal neurotransmitter metabolite panel means Bertrand doesn't have a pediatric neurotransmitter disease such as:

• Succinic Semialdehyde Dehydrogenase Deficiency (SSADH)
• Tyrosine Hydroxylase Deficiency (TH)
• Aromatic L-Amino Acid Decarboxylase Deficiency (AADC)
• Guanosine Triphosphate Cyclohydrolase I Deficiency(GCH I, GTP
• Cyclohydrolase, GTPCH)
• Sepiapterin Reductase Deficiency (SR)

As mentioned before, the normal purine panel means no Lesch-Nyhan, but it also rules out quite a few other diseases, such as those listed below in case you are curious.

Disorders of Purine Salvage

• Lesch-Nyhan syndrome
• Adenine phosphoribosyltransferase deficiency

Disorders of Purine Nucleotide Synthesis

• Phosphoribosylpyrophosphate synthetase superactivity
• Adenylosuccinase deficiency

Disorders of Purine Catabolism

• Myoadenylate deaminase deficiency
• Adenosine deaminase deficiency
• Purine nucleoside phosphorylase deficiency
• Xanthine oxidase deficiency

Disorders of Pyrimidine Metabolism

• Uridine monophosphate synthase deficiency