The SALSA MLPA
Probemix P330 PCDH19 is a research use only (RUO)
assay for the detection of deletions or duplications in the protocadherin-19 gene (PCDH19
) located at chromosome Xq22.1, which is associated with early infantile epileptic encephalopathy-9 (EIEE9), better known as epilepsy female-restricted with mental retardation (EFMR).
EFMR is characterised by seizure with onset in infancy or early childhood and cognitive impairment. Additional features include delayed development of variable severity, autistic signs and psychosis. Despite an X-linked mode of inheritance, which usually affects male carriers, this disease is restricted to females. This is probably due to a mechanism called cellular interference (Niazi et al. 2019). PCDH19
is subject to X-chromosome inactivation, which leads to a homogeneous population of cells negative for PCDH19
in males. In heterozygous females, on the other hand, the presence of both PCDH19
-positive and PCDH19
-negative cells affects the communication between the cells and leads to EFMR.
The SALSA MLPA Probemix P330-A4 PCDH19 contains 39 MLPA probes with amplification products between 130 and 484 nucleotides (nt). This includes 14 probes for the PCDH19
gene, at least two probes for each exon, with the exception of exon 2 for which no probe has been included. Furthermore, this probemix contains seven probes upstream and eight probes downstream of the PCDH19
gene. In addition, ten reference probes are included that detect locations on the X-chromosome. Complete probe sequences and the identity of the genes detected by the reference probes are available online (www.mlpa.com
This probemix contains nine quality control fragments generating amplification products between 64 and 105 nt: four DNA Quantity fragments (Q-fragments), two DNA Denaturation fragments (D-fragments), one Benchmark fragment, and one chromosome X and one chromosome Y-specific fragment. More information on how to interpret observations on these control fragments can be found in the MLPA General Protocol and online at www.mlpa.com