Arginase deficiency presenting with cerebral oedema and failure to thrive

Arginase I mRNA therapy - a novel approach to rescue arginase 1 enzyme deficiency

Arginase I (ARG1) deficiency is an autosomal recessive urea cycle disorder, caused by deficiency of the enzyme Arginase I, resulting in accumulation of arginine in blood. Current Standard of Care (SOC) for ARG1 deficiency in patients or those having detrimental mutations of ARG1 gene is diet control. Despite diet and drug therapy with nitrogen scavengers, ~25% of patients suffer from severe mental deficits and loss of ambulation. 75% of patients whose symptoms can be managed through diet therapy continue to suffer neuro-cognitive deficits. In our research, we demonstrate in vitro and in vivo that administration of ARG1 mRNA increased ARG1 protein expression and specific activity in relevant cell types, including ARG1-deficient patient cell lines, as well as in wild type mice for up to 4 days. These studies demonstrate that ARG1 mRNA treatment led to increased functional protein expression of ARG1 and subsequently an increase in urea. Hence, ARG1 mRNA therapy could be a potential treatment option to develop for patients.

Mid-career research training for the generalist physician: case study of a balancing act

BACKGROUND

Although generalist physician faculty typically lack the skills needed to conduct research, few medical schools offer on-site faculty development programs that teach research skills.

DESCRIPTION

To address this dilemma, our medical school introduced a part-time Primary Care Research Fellowship offering full-day classes once a week over 10 months.

EVALUATION

We asked the 22 general internists, general pediatricians, and family physicians who participated in the program to rate their experience, and we measured their research productivity during the 3 years before and 3 years after completing the program, using a group of matched controls for comparison. Participants rated the program highly and increased their aggregate research productivity from 1 publication before completing the program to 6 publications afterward, although this increase did not reach statistical significance (p = .09). Controls exhibited substantially higher baseline productivity than fellows (10 publications vs. 1 publication, p = .03), but controls' productivity changed little between the first and second measurement periods (10 and 7 publications, respectively).

CONCLUSION

Our mid-career research training program enabled primary care academic faculty to gain confidence in their ability to conduct a scientific study with minimal disruption to their teaching and clinical activities.

Arginase deficiency with lethal neonatal expression: evidence for the glutamine hypothesis of cerebral edema

We describe a rare and lethal case of arginase deficiency in a 2-day-old female infant with encephalopathy and cerebral edema. The levels of glutamine and arginine but not ammonia were markedly elevated, lending support to the "glutamine hypothesis" as the mechanism of cerebral edema in urea cycle defects.