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New publication by Bestcilia partner: further insight into PCD through a study on the Irish Traveller population

Dr. Jane S. Lucas, Bestcilia partner associated with WP4, has recently published a noteworthy article highlighting the challenges of PCD diagnostics. The publication is another installment in a series of case reports of studies on PCD performed on members of the Irish Traveller population. The article focuses on a rare combination of a single gene and chromosome disorder, resulting (respectively) in PCD symptoms and developmental delay.  

PCD is often accompanied by various laterality defects; 20 out of 29 causative genes may potentially lead to organ laterality defects. It is, however, very rarely associated with developmental delay. The article in question describes a case of an Irish Traveller family with children suffering from both PCD and related laterality defects as well as various forms of developmental delay, including speech impairment. In this particular family, gene mutations resulting in PCD with laterality defects (RSPH4A, DYX1C1 and CCNO) described in previous publications on the Irish Traveller population were excluded, indicating a novel mutation. Using exome sequencing allowed the researchers to identify a minor, but significant mutation in the CCDC103 gene, which accounts for the PCD syptoms and laterality defects. Mutations in CCDC103 are, however, unlikely to result in developmental delay; it was thus clear that the developmental delay in the Irish Traveller family stemmed from a distinct causative factor and was not related to PCD. Additional tests revealed that CCDC103 mutation on chromosome 17 was coupled by a microduplication at 17q12 and that it was the latter lesion that was responsible for speech and language impairment in the Irish Traveller patients.

The results of the study shed light on the challenges of PCD diagnostics by drawing attention to the rare co-existence of a single gene and chromosome disorder; this combination is highly unusual, but accounts for a spectrum of clinical features which may otherwise be incorrectly assumed to be caused by the same factor. Additionally, the study helped to identify yet another PCD gene in the relatively small Irish Traveller population, bringing the count to four, with more potential PCD genes expected to surface. This is an unexpected and surprizing development, given the extensive genetic heterogeneity usually associated with PCD.

Full article can be accessed here.