[5] This has led to speculation and further to the proposal that Pcdhs may provide a synaptic-address code for neuronal connectivity or a single-cell barcode for self-recognition/self-avoidance similar to that ascribed to DSCAM proteins of invertebrates.

Although vertebrate DSCAMs lack the diversity of their invertebrate counterparts, the selective transcription of individual Pcdh isoforms can be achieved by promoter choice followed by alternative pre-mRNA cis-splicing thus increasing the number of possible combinations.

Clustered Pcdhs proteins are detected throughout the neuronal soma, dendrites and axons and are observed in synapses and growth cones.

[6][7][8][9][10] Like classical cadherins, members of Pcdhs family were also shown to mediate cell-cell adhesion in cell-based assays[11][12][13] and most of them showed to engage in homophilic trans-interactions.

Since these molecules are involved in so many developmental processes like axon guidance and dendrite arborization, mutations in Pcdhs genes and their expression may play a role in Down, Rett as well as Fragile X syndrome,[19] schizophrenia,[20] and neurodegenerative diseases[21] The cytoplasmic domain of Pcdh-alpha can be divided into two specific types.