Cystic fibrosis: terminology and diagnostic algorithms

Area of Science:

• Medical Science
• Genetics
• Pulmonology

Background:

• Cystic Fibrosis (CF) exhibits significant clinical heterogeneity.
• Patients present with varying disease severity, from classic infantile manifestations to milder, atypical forms.
• Accurate classification is essential for prognosis and management.

Purpose of the Study:

• To propose standardized terminology for classifying CF based on clinical presentation and diagnostic criteria.
• To differentiate between classic/typical CF and non-classic/atypical CF.
• To guide a structured diagnostic process for CF.

Main Methods:

• Defining classic CF: presence of phenotypic characteristics and sweat chloride concentration >60 mmol/l.
• Defining non-classic CF: CF phenotype in at least one organ system and normal (<30 mmol/l) or borderline (30-60 mmol/l) sweat chloride levels.
• Diagnostic confirmation for non-classic CF involves CFTR gene mutation analysis or CFTR dysfunction measurement (nasal potential difference).

Main Results:

• Classic CF patients typically have >1 CFTR mutation and can present with pancreatic insufficiency or sufficiency, with variable disease severity.
• Non-classic CF patients often have pancreatic sufficiency and milder lung disease, with single or multi-organ involvement.
• Algorithms for a structured diagnostic approach are proposed.

Conclusions:

• Standardized terminology aids in distinguishing CF patient categories.
• This classification supports tailored diagnostic and management strategies.
• Further research may refine diagnostic algorithms for CF heterogeneity.