Respiratory Disorders

3 conditions|1 ABGC-listed

Overview

This chapter covers genetic conditions primarily affecting the respiratory system. Cystic fibrosis is the most clinically central, with key concepts around CFTR variant classes and carrier screening.

Alpha-1 antitrypsin deficiency

A 40-year-old non-smoker presents with early-onset emphysema predominantly affecting the lower lobes. His brother has cirrhosis.

Cystic fibrosis

ABGC

A newborn with meconium ileus is found to have an elevated immunoreactive trypsinogen on newborn screening. Sweat chloride is 85 mEq/L. Genetic testing reveals F508del homozygosity.

Primary ciliary dyskinesia (Kartagener syndrome)

A child with chronic sinusitis, recurrent otitis media, and bronchiectasis has dextrocardia on chest X-ray. Nasal nitric oxide is markedly low.

Summary Table

Disorder	Gene	Inheritance	Cardinal Features
Cystic fibrosis	CFTR	AR	Lung infections, pancreatic insufficiency, male infertility
PCD/Kartagener	Ciliary genes	AR	Sinopulmonary disease, situs inversus (~50%)
A1AT deficiency	SERPINA1	AR	Early COPD, liver disease

Summary Table

Disorder	Gene	Inheritance	Cardinal Features
Cystic fibrosis	CFTR	AR	Lung infections, pancreatic insufficiency, male infertility
PCD/Kartagener	Ciliary genes	AR	Sinopulmonary disease, situs inversus (~50%)
A1AT deficiency	SERPINA1	AR	Early COPD, liver disease

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