The role of biochemical testing in cystic fibrosis

INTRODUCTION: Cystic fibrosis (CF) is a life-limiting autosomal recessive disorder as a result of CF transmembrane conductance regulator gene mutation. It has a wide range of disease severity in patients with the same genotype.

CASE REPORT: A 5-year-old Malay boy with a history of recurrent pneumonia, presented with productive cough, fever and worsening tachypnoea. Physical examination revealed coarse crepitations, reduced breath sounds and clubbing. Biochemical investigations showed that he had respiratory type 2 failure as a result of bronchiectasis. Sweat conductivity done twice was raised supporting a diagnosis of CF. Other investigations such as bronchoscopy to look for congenital anomaly of the lung, infectious disease screening and tuberculosis, fungal and viral culture and sensitivity were negative. Further cascade screening revealed high sweat conductivity results in his siblings.

DISCUSSION: Although CF prevalence is low in Malaysia, it is nevertheless an important diagnosis to be recognised as it is associated with increased morbidity.