Amino Acid Disorders |
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| Disease Name | Argininemia/ arginase deficiency |
| Alternate name(s) | Hyperargininemia ARG I Deficiency |
| Acronym | ARG I |
| Disease Classification | Amino Acid Disorder |
| Variants | Yes |
| Variant name | ARG II |
| Symptom onset | Primarily neonatal but also infancy and childhood |
| Symptoms | Spastic diplegia or tetraplegia, opisthotonos, seizures, acquired microcephaly, hepatomegaly, vomiting, anorexia and irritability. Coma and death due to hyperammonemia have been reported. |
| Natural history without treatment | Developmental delay due to hyperargininemia or hyperammonemia. Neurologic damage can include spasticity, hyperactivity, ataxia, seizures and cerebral atrophy. |
| Natural history with treatment | If treatment occurs prior to catastrophic hyperammonemia, normal outcome is possible but not proven. Treatment can decrease some of the neurologic symptoms but complete reversal is not likely. |
| Treatment | Dietary restriction of arginine, protein restriction and supplementation of amino acids other than arginine. Sodium benzoate therapy. |
| Other | Spastic diplegia or tetraplegia |
| Physical phenotype | No physical dysmorphisms but may be thought to have cerebral palsy |
| Inheritance | Autosomal recessive |
| General population incidence | Rare (1:300,000) |
| Ethnic differences | No |
| Population | N/A |
| Ethnic incidence | N/A |
| Enzyme location | Liver and erythrocytes |
| Enzyme Function | Terminal enzyme of the urea cycle which hydrolyzes arginine to urea and ornithine to dispose of excess nitrogen |
| Missing Enzyme | arginase |
| Metabolite changes | Increased arginine in plasma, urine and cerebrospinal fluid. Increased amino acids (lysine, cystine, ornithine) in blood and urine. Hyperammonemia. |
| Gene | ARG1 |
| Gene location | 6p23 |
| DNA testing available | On a research basis only |
| DNA testing detail | No common mutations known |
| Prenatal testing | Difficult due to lack of enzyme expression in fibroblasts. Direct fetal blood sampling is a possibility. Prenatal testing by direct DNA testing is not possible due to lack of common mutation. May be possible by RFLPs. |
| MS/MS Profile | Arginine and citrulline elevated. Arg - 152-1756uM |
| OMIM Link | http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=207800 |
| Genetests Link | http://genetests.org |
| Support Group |
National Urea Cycle Disorders Foundation http://www.nucdf.org/ National Coalition for PKU and Allied Disorders http://www.pku-allieddisorders.org/ Children Living with Inherited Metabolic Diseases http://www.climb.org.uk/ |
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