ABSTRACT
BACKGROUND: Neonatal intrahepatic cholestasis caused by citrin deficiency (CD) is a rare inborn error of metabolism due to variants in the SLC25A13 gene encoding the calcium-binding protein citrin. Citrin is an aspartate-glutamate carrier located within the inner mitochondrial membrane. CASE PRESENTATION: We report on two siblings of Romanian-Vietnamese ancestry with citrin deficiency. Patient 1 is a female who presented at age 8 weeks with cholestasis, elevated lactate levels and recurrent severe hypoglycemia. Diagnosis was made by whole exome sequencing and revealed compound heterozygosity for the frameshift variant c.852_855del, p.Met285Profs*2 and a novel deletion c.(69 + 1_70-1)_(212 + 1_231-1)del in SLC25A13. The girl responded well to dietary treatment with a lactose-free, MCT-enriched formula. Her younger brother (Patient 2) was born 1 year later and also found to be carrying the same gene variants. Dietary treatment from birth was able to completely prevent clinical manifestation until his current age of 4.5 months. CONCLUSIONS: As CD is a well-treatable disorder it should be ruled out early in the differential diagnosis of neonatal cholestasis. Due to the combination of hepatopathy, lactic acidosis and recurrent hypoglycemia the clinical presentation of CD may resemble hepatic mitochondrial depletion syndrome.
Subject(s)
Cholestasis, Intrahepatic , Cholestasis , Citrullinemia , Citrullinemia/diagnosis , Citrullinemia/genetics , Female , Humans , Infant , Infant, Newborn , Male , Mitochondrial Membrane Transport Proteins/genetics , MutationABSTRACT
Some leguminous species of the genus Aeschynomene are specifically stem-nodulated by photosynthetic bradyrhizobia. To study the effect of bacterial photosynthesis during symbiosis, we generated a photosynthesis-negative mutant of the Bradyrhizobium sp. strain ORS278 symbiont of Aeschynomene sensitiva. The presence of a functional photosynthetic unit in bacteroids and the high expression of the photosynthetic genes observed in stem nodules demonstrate that the bacteria are photosynthetically active during stem symbiosis. Stem inoculation by the photosynthetic mutant gave a 50% decrease in stem-nodule number, which reduced nitrogen fixation activity and plant growth in the same proportion. These results indicate an important role of bacterial photosynthesis in the efficiency of stem nodulation.
Subject(s)
Bacterial Proteins , Bradyrhizobium/physiology , Fabaceae/microbiology , Light-Harvesting Protein Complexes , Photosynthesis/physiology , Photosynthetic Reaction Center Complex Proteins/metabolism , Plants, Medicinal , Base Sequence , Bradyrhizobium/genetics , DNA, Bacterial , Gene Expression , Heme Oxygenase (Decyclizing)/genetics , Heme Oxygenase (Decyclizing)/metabolism , Molecular Sequence Data , Mutagenesis , Operon , Phenotype , Photosynthetic Reaction Center Complex Proteins/genetics , SymbiosisABSTRACT
A carotenoid biosynthesis gene cluster involved in canthaxanthin production was isolated from the photosynthetic Bradyrhizobium sp. strain ORS278. This cluster includes five genes identified as crtE, crtY, crtI, crtB, and crtW that are organized in at least two operons. The functional assignment of each open reading frame was confirmed by complementation studies.
