Dual-allele heterozygous mutation of DNAH5 gene in a boy with primary ciliary dyskinesia: A case report

Rationale: To analyze clinical and imaging features, ciliary structure and family gene mutation loci of a primary ciliary dyskinesia (PCD) boy with a dual-allele heterozygous mutation of DNAH5.Patient concerns: Clinical data of the proband and relatives. Electronic bronchoscopy, transmission electron microscope (TEM) of the cilia and next-generation sequencing (NGS) were performed. PCD-related DNAH5 exon mutation sites were searched.Diagnoses: A 10-year and 10-month-old boy was hospitalized due to "recurrent cough, expectoration, sputum and shortness of breathing after activity for over 7 years, and aggravated for 1 week." Moderate and fine wet rales were detected in bilateral lungs. Clubbing fingers and toes were observed. In local hospitals, he was diagnosed with Mycoplasma pneumoniae infection and Streptococcus pneumoniae was cultured.Interventions: Pulmonary function testing showed mixed ventilation dysfunction and positive for bronchial dilation test. Imaging examination and fiberoptic bronchoscopy revealed transposition of all viscera, bilateral pneumonia, and bronchiectasis. TEM detected no loss of the outer dynein arms. NGS identified 2 mutations (c.4360C>T, c.9346C>T) in the DNAH5 gene inherited from healthy parents.Outcomes: According to literature review until 2022, among 144 exon gene mutations causing amino acid changes, C>T mutation is the most common in 44 cases, followed by deletion mutations in 30 cases. Among the amino acid changes induced by gene mutation, terminated mutations were identified in 89 cases.Lessons: For suspected PCD patients, TEM and NGS should be performed. Prompt diagnosis and treatment may delay the incidence of bronchiectasis and improve clinical prognosis.