The Palestinian primary ciliary dyskinesia (PCD) cohort: clinical, diagnostic and genetic spectrum

Abstract

Background: Diagnostic testing for PCD started in 2013 in Palestine. We aimed to describe the clinical, diagnostic and genetic spectrum of the Palestinian PCD cohort.

Methods: 390 individuals with symptoms suggestive of PCD and 74 family members underwent nasal nitric oxide (nNO); and/or transmission electron microscopy (TEM); and/or PCD genetic panel or whole exome testing. Clinical characteristics were collected close to diagnosis including FEV1 GLI z-scores and BMI z-scores.

Results: 82 had a definite positive PCD diagnosis (TEM and/or genetics) and 103 were highly likely (Kartagener’s and/or low nNO). Positive cases (n=82) had median age of 13.5 years (range 0-43), were highly consanguineous (95%) and 100% Arabic descent. Clinical features included persistent wet cough (95%), neonatal respiratory distress (79%), clubbing (21%) and situs inversus (41%). Lung function at diagnosis was already impaired FEV1 z-score mean -1.49 (sd=1.79) and BMI z-score mean -0.30 SD=1.4. 69 families were genotyped. 59 individuals from 42 families (60%) had mutations in 14 PCD-genes; CCDC39 (26% of families), DNAH11 (17%) and LRRC6 (12%) were the most common. 16% had mutations in candidate genes, 24% had no variants identified. 100% of variants were homozygous. TEM defects and genotype associations were as expected.

Conclusions: Despite limited local resources, collaborations during the last 7-years have facilitated detailed geno- and phenotyping of one of the largest PCD cohorts globally. nNO identifies likely cases and targeted genetic testing, conducted locally, can now identify specific mutations in known families.