General information
The SALSA MLPA
Probemix P279 CACNA1A is a
research use only (RUO) assay for the detection of deletions or duplications in the genes
CACNA1A, which is associated with familial hemiplegic migraine and episodic ataxia 2, and
KCNA1, which is involved in episodic ataxia 1.
Familial hemiplegic migraine (FHM) falls within the category of migraine with aura and is characterised by hemiparesis in combination with at least one symptom of aura, such as visual disturbance, sensory loss, and dysphasia. Neurologic deficits with FHM attacks can be prolonged for hours to days and may outlast the associated migrainous headache. Approximately 7% of FHM cases are attributed to pathogenic variants of
CACNA1A, located on chromosome 19p13.13. Other genes, including
SCN1A,
ATP1A2 and
PRRT2 have also been associated to FHM. These genes are covered by probemixes P137 SCN1A and P348 ATP1A2-CACNA1A-PRRT2.
Episodic ataxia type 2 (EA2) involves episodes of ataxia including vertigo and nausea. Attacks can also be associated with dysarthria, diplopia, tinnitus, dystonia, hemiplegia and headache, and typically last minutes to days. EA2 is caused by pathogenic variants of
CACNA1A and is inherited in an autosomal dominant manner. Overlap has been described between the FHM phenotype associated with pathogenic missense variants of
CACNA1A and EA2.
Episodic ataxia type 1 (EA1) is characterized by constant myokymia and episodes of spastic contractions of the skeletal muscles of the head, arms, and legs with loss of both motor coordination and balance. During attacks individuals may experience a number of variable symptoms including vertigo, blurred vision, diplopia, nausea, headache, diaphoresis, clumsiness, stiffening of the body, dysarthric speech, and difficulty in breathing. EA1 is caused by pathogenic variants of
KCNA1, located on chromosome 12p13.32, and is inherited in an autosomal dominant manner.
More information is available for
Familial hemiplegic migraine:
https://www.ncbi.nlm.nih.gov/books/NBK1501/
Episodic ataxia type 2:
https://www.ncbi.nlm.nih.gov/books/NBK1388/
Episodic ataxia type 1:
https://www.ncbi.nlm.nih.gov/books/NBK25442/
This SALSA MLPA Probemix is not CE/FDA registered for use in diagnostic procedures. Purchase of this product includes a limited license for research purposes.
Probemix content
The SALSA MLPA Probemix P279-C1 CACNA1A contains 46 MLPA probes with amplification products between 130 and 487 nucleotides (nt). This includes 34 probes for the
CACNA1A gene, one flanking probe targeting the
LDLR gene downstream of
CACNA1A, and two probes for the
KCNA1 gene. In addition, nine reference probes are included that detect autosomal chromosomal locations. 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.