{'fraction_non_alphanumeric': 0.023233301064859633, 'fraction_numerical': 0.001936108422071636, 'mean_word_length': 5.939597315436242, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Genetics of psoriatic arthritis

The psoriatic phenotype is clinically heterogeneous with psoriatic arthritis (PsA) itself being heterogeneous. Studies have consistently demonstrated that PsA has a strong genetic component and disease pathogenesis encompasses a complex interplay between genetic, immunological, and environmental factors. In this chapter, we will review the genetics of PsA including the major histocompatibility complex (MHC) region and non-MHC loci. We will detail how susceptibility genes can be grouped into barrier integrity, innate immune response, and adaptive immune response (particularly Th-17 lymphocyte signalling). We will articulate how these studies strongly support PsA as genetically different from PsV and that the genetic heterogeneity is likely attributed to different HLA susceptibility alleles within the MHC region that an individual carries. Furthermore, we will highlight new emerging technologies, in particular, next-generation sequencing, which may lead to new genetic discoveries in PsA.