Laboratory diagnosis of creatine deficiency syndromes: a technical standard and guideline of the American College of Medical Genetics and Genomics.

Disclaimer: These ACMG Standards and Guidelines are intended as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these standards and guidelines is voluntary and does not necessarily assure a successful medical outcome. These Standards and Guidelines should not be considered inclusive of all proper procedures and tests or exclusive of others that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, clinical laboratory geneticists should apply their professional judgment to the specific circumstances presented by the patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient's record the rationale for the use of a particular procedure or test, whether or not it is in conformance with these Standards and Guidelines. They also are advised to take notice of the date any particular guideline was adopted, and to consider other relevant medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures.Cerebral creatine deficiency syndromes are neurometabolic conditions characterized by intellectual disability, seizures, speech delay, and behavioral abnormalities. Several laboratory methods are available for preliminary and confirmatory diagnosis of these conditions, including measurement of creatine and related metabolites in biofluids using liquid chromatography-tandem mass spectrometry or gas chromatography-mass spectrometry, enzyme activity assays in cultured cells, and DNA sequence analysis. These guidelines are intended to standardize these procedures to help optimize the diagnosis of creatine deficiency syndromes. While biochemical methods are emphasized, considerations for confirmatory molecular testing are also discussed, along with variables that influence test results and interpretation.Genet Med 19 2, 256-263.

[Urinary enzymes as markers of functional state of kidneys with diabetic lesions].

Activity of tubular lysosomic (N-acetyl-beta-D-glucosaminidase--NAG, its thermostable isoenzyme NAG B and B-galactosidase--beta-GAL) and mitochondrial (L-canavanine: ornithine amidinetransferase--COAT) enzymes were measured in urine of 30 patients with diabetes complicated by diabetic nephropathy (DN). It was shown that activity of NAG, especially its thermostable isoenzyme NAG B and also beta-GAL in urine of DN patients was higher compare to those in healthy subject. Moreover COAT activity was registered in urine of DN patients while it is not presented in healthy persons. The precise dependence of NAG, NAG B, beta-GAL levels and COAT activity on the functional state of renal parenchyma in particular on tubular nephron nephrocytes was found that allows us to consider the given parameters as markers of diabetic process progressing in kidneys in patients with diabetes.