Mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene typically cause severe health complications in multiple organ systems, including the respiratory and gastrointestinal systems. Certain CFTR mutations, however, cause milder clinical phenotypes which may delay confirmatory diagnosis and treatment. Moreover, rare CFTR variants are not studied frequently or approved for genotype specific CFTR modulator therapies, creating further disadvantage. Herein, we describe a personalized medicine approach for a CF patient with three CFTR variants and mild clinical disease to aid in the diagnosis of CF and development of an optimized treatment plan. This strategy relied on the synergistic combination of advanced genetic analyses, patient-derived models of CFTR function and modulation, and personalized clinical care delivery. Whole Exome Sequencing revealed three compound heterozygous CFTR variants: c.2249C>T (p.P750L), c.1408G>A (p.V470M), and c.1251C>A (p.N417K). The CFTR channel function and nature of protein defects for both V470M and N417K mutations are not previously characterized. Patient-derived intestinal organoid models demonstrated residual CFTR channel activity, with improvement in channel function following treatment with the CFTR modulators. / n vitro studies in heterologous model system demonstrated that P750L has the features of Class II CFTR mutations, whereas V470M/N417K exhibited characteristics of Class II, III, and IV mutations, with all three variants responding to the combination modulator therapy of elexacaftor, tezacaftor, and ivacaftor (ETI) and showing functional rescue to near-wild-type CFTR levels. The laboratory data was then utilized to inform patient care, including off-label prescription of ETI. Following 18 months of ETI therapy, significant improvements were noted in key clinical outcomes, including sweat chloride, nutritional parameters, and respiratory and gastrointestinal symptoms. This study demonstrates a personalized medicine approach across clinical and laboratory domains used to care for CF patients with atypical symptoms and/or rare CFTR mutations.
Discussed is the case of a 13-year-old male with no significant past medical history, who presented to the hospital for evaluation of multisystem inflammatory syndrome in children (MIS-C). He arrived with findings of conjunctivitis, strawberry tongue, tachycardia at rest, and hypoxemia with oxygen saturation of 85%. The patient was recently hospitalized 1 week prior for viral pneumonia and hypoxemia due to SARS-CoV-2. During his inpatient stay he received combination therapy of remdesivir and dexamethasone. Following, he weaned to room air and his pulse oximetry (SaO2) order was switched to intermittent with floor vitals prior to his discharge.
Background Cystic Fibrosis (CF) and autism spectrum disorder (ASD) are life-long conditions with intense treatment burdens for patients and families. Patients with a concurrent diagnosis (CF-ASD) experience unique challenges to CF care. This study describes the experiences of our multidisciplinary CF team in caring for patients with CF-ASD and provides insight into provider and parental perspectives on clinical management. Methods This is a three-part IRB-approved study involving 1) retrospective chart review of patients with CF-ASD, 2) qualitative interviews with multi-disciplinary care teams, and 3) qualitative interviews with caregivers of patients with CF-ASD. Challenges in clinical management of this specific cohort were compiled using data from chart review and care team interviews. Strategies to address these challenges were identified and rated by individual families based on relevance and practicality. Results Within our CF center, 12 patients have an official diagnosis of ASD. Median age of patients with CF-ASD was 8.5 years (range 3-20 years), 75% were male, and 83% were on highly effective modulator therapy. Clinical challenges included sensory processing issues, environmental overstimulation, intolerance to procedures and disrupted routines. Potentially impactful strategies include patient-specific coping plans, guided behavioral interventions, parental advocacy, and improved communication between the family and multidisciplinary team. Conclusions Children with CF-ASD face extraordinary challenges beyond the experience of neurotypical children with CF. Increased awareness of this complex dual diagnosis will help providers be sensitive to the unique needs of these patients, to help build consistent and trustworthy relationships with families, and to provide effective clinical care despite limitations.