Ornithine Transcarbamylase Deficiency Follow-up
- Author: Karl S Roth, MD; Chief Editor: Luis O Rohena, MD more...
Further Outpatient Care
A biochemical geneticist must oversee patient care because the metabolic integrity of such individuals with ornithine transcarbamylase (OTC) deficiency is very tenuously poised.
Proper nutrition does not follow the usual nutritional rules, and any variations from what is appropriate may result in disaster. This is true throughout life but mostly in the growing infant and adolescent child in whom requirements may fluctuate weekly and must be closely monitored.
Scrupulous adherence to the dietary and medication recommendations is mandatory for survival. Under no circumstances should this be undertaken by a general physician without close guidance from an expert in the care of patients with inherited metabolic diseases.
Most affected male infants with neonatal presentation have not escaped the initial episode with normal mentation. Nonetheless, survival for many years can be achieved with very careful monitoring; use of oral citrulline, benzoate, and phenylacetate; and scrupulous dietary attention.
Prognosis for older males with initial onset remains unclear because so many remain undiagnosed until very late in the clinical course.
Most heterozygous females appear to be relatively healthy, except for a propensity to develop severe headaches with high protein intake. Women and children who are mildly affected can have an excellent prognosis with proper care.
The long-term outlook for individuals with all forms of OTC deficiency is guarded, particularly with reference to cerebral function.
Family pedigree studies in this disease are essential for the following 2 reasons:
The X-linked nature of the mutation leads to a 1:2 chance of recurrence in any subsequent male conceptus if the mother is a carrier.
All female siblings of the obligate heterozygous maternal carrier are potential carriers, whereas male siblings may be at risk for late-onset presentation. The second reason is derived from the first.
Another compelling issue in family counseling is the overwhelming sense of guilt with which the carrier mother must deal.
Finally, repeatedly reinforce the parents in their abilities to perceive early signs of hyperammonemia and to take immediate steps to obtain medical care. Prenatal diagnosis is possible.
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