Background: Cartilage-hair hypoplasia (CHH), caused by mutations in the ribonuclease mitochondrial RNA-processing (RMRP) gene, is associated with diverse immune abnormalities including combined immune deficiency (CID). Most patients with CHH are managed with supportive measurements, while few have received allogeneic hematopoietic stem cell transplantations (HSCT). The progression of the immune abnormalities and the impact of HSCT in patients with CHH and CID have not been well characterized.Methods: The clinical and laboratory findings of 2 siblings diagnosed in infancy with CHH and CID due to the common 70A>G mutation in RMRP, including the effects of HSCT performed in 1 of them, were compared.Results: Both patients suffered from recurrent respiratory infections at early age with reduced T cells numbers and responses. Patient 1 immune function continued to deteriorate leading to HSCT from an HLA-matched sibling at 4.5 years of age. The patient suffered acute and chronic graft versus host disease of the skin with residual mild joint contractures and scleroderma-like skin changes. Seven years after HSCT patient 1 has normal immune function. Immune evaluations of patient 2 in the first years of life indicated mild improvement. The patient did not have a suitable related HSCT donor and the family elected to continue with supportive care. At 7 years of age, patient 2 is clinically well and thriving with persistent T cell abnormalities.Conclusions: Close monitoring of immune function in early life for patients with CHH and CID as well as the availability of suitable donors assists in determining management, including HSCT.Statement of novelty: The manuscript demonstrates the importance of close monitoring and personalized approach in the management of patients affected by CHH.

Background: The effects of disruptions in the lives of the adolescent Primary Immunodeficiency (PI) patient require psychosocial staff involved in their care to find unique approaches to treatment. The demands of living with PI in adolescence complicates this already turbulent life cycle transition. Absence from school due to infections and treatment can lead to social isolation and in turn issues of self-esteem, creating challenges for teenagers with chronic diseases. The importance of maintaining social support with peers and developing a new network of social supports with teens with similar diagnoses is highlighted in the literature as an important factor in helping teens successfully cope with the demands of chronic illness.Methods: To best meet the complex needs of this population, the PI Teen Outreach Program was created in 2010. The goal was to connect teens with PI to one another in an environment that engages them in “normal” activities while providing an opportunity to discuss diagnosis, coping, and the impact of living with PI. The program consists of group teen events that involve an activity for peers to connect followed by a meal for sharing of life experiences. Community peers are invited to assist teens in demystifying their PI disease to their community friends.Results: At the conclusion of each outreach event, teens were given an anonymous evaluation utilizing both Likert scales and qualitative narrative comments. The positive feedback highlights the importance of providing creative and unique programs for this population.Conclusion: A diagnosis of PI can be difficult for teenagers as they cope with the developmental tasks of adolescence alongside a chronic illness. The Teen Outreach Program has been successful in enhancing the psychosocial support and normalizing the experience of teenagers with PI.Statement of novelty: There is a paucity of literature addressing the psychosocial issues that the PI teen population face and any novel programming to address their unique needs.