Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_ModeratePM2
The NM_001385593.1(ARPP21):c.936-1G>A variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.0000201 in 1,594,220 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).
ARPP21 (HGNC:16968): (cAMP regulated phosphoprotein 21) This gene encodes a cAMP-regulated phosphoprotein. The encoded protein is enriched in the caudate nucleus and cerebellar cortex. A similar protein in mouse may be involved in regulating the effects of dopamine in the basal ganglia. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jun 2012]
Verdict is Uncertain_significance. Variant got 4 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.022012578 fraction of the gene. Cryptic splice site detected, with MaxEntScore 8.6, offset of -3, new splice context is: atcatgtttttcatttccAGtaa. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
PM2
Very rare variant in population databases, with high coverage;
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Oct 29, 2021
The c.938G>A (p.R313K) alteration is located in exon 13 (coding exon 11) of the ARPP21 gene. This alteration results from a G to A substitution at nucleotide position 938, causing the arginine (R) at amino acid position 313 to be replaced by a lysine (K). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -