Omenn Syndrome : Two Case Reports

Omenn syndrome is a variant of combined severe immunodeficiencydue to mutations in RAG genes. It is characterized by polymorph symptoms andlethal outcome. We report on two cases of Omenn syndrome. Infants were aged 50and 46 days. The clinical and biological signs were typical and complete in the firstcase. In the second case, only the cutaneous signs were present. Diagnosis was confirmedby genetic study. The Rag1 T631 mutation was found in these two patients.Hematopoietic stem cell transplantation could not be done and the evolution wasfatal in both cases because of severe infectious episodes. Prenatal diagnosis wasperformed in the two families and each family has currently a healthy child. In conclusion,early diagnosis of Omenn syndrome may avoid infectious complicationsresponsible for delay in therapeutic management. Genetic study confirms the diagnosis.The treatment usually consists of hematopoietic stem cell transplantationin association with immunosuppressive drugs. Prenatal diagnosis is very importantto allow parents to have healthy children.</p

Biallelic mutations of methionyl-tRNA synthetase cause a specific type of pulmonary alveolar proteinosis prevalent on R&eacute;union Island.

Methionyl-tRNA synthetase (MARS) catalyzes the ligation of methionine to tRNA and is critical for protein biosynthesis. We identified biallelic missense mutations in MARS in a specific form of pediatric pulmonary alveolar proteinosis (PAP), a severe lung disorder that is prevalent on the island of R&eacute;union and the molecular basis of which is unresolved. Mutations were found in 26 individuals from R&eacute;union and nearby islands and in two families from other countries. Functional consequences of the mutated alleles were assessed by growth of wild-type and mutant strains and methionine-incorporation assays in yeast. Enzyme activity was attenuated in a liquid medium without methionine but could be restored by methionine supplementation. In summary, identification of a founder mutation in MARS led to the molecular definition of a specific type of PAP and will enable carrier screening in the affected community and possibly open new treatment opportunities