Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_000304.4(PMP22):c.280_281delGGinsT(p.Gly94SerfsTer17) variant causes a frameshift, missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G94S) has been classified as Uncertain significance.
PMP22 (HGNC:9118): (peripheral myelin protein 22) This gene encodes an integral membrane protein that is a major component of myelin in the peripheral nervous system. Studies suggest two alternately used promoters drive tissue-specific expression. Various mutations of this gene are causes of Charcot-Marie-Tooth disease Type IA, Dejerine-Sottas syndrome, and hereditary neuropathy with liability to pressure palsies. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]
PMP22 Gene-Disease associations (from GenCC):
Charcot-Marie-Tooth disease type 1A
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Laboratory for Molecular Medicine, Ambry Genetics
hereditary neuropathy with liability to pressure palsies
Our verdict: Pathogenic. The variant received 12 ACMG points.
PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 35 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 17-15239509-CC-A is Pathogenic according to our data. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-15239509-CC-A is described in CliVar as Pathogenic. Clinvar id is 220861.Status of the report is criteria_provided_single_submitter, 1 stars.
This sequence change deletes 2 nucleotides and inserts 1 nucleotide in exon 4 of the PMP22 mRNA (c.280_281delinsT), causing a frameshift at codon 94. This creates a premature translational stop signal in the last exon of the PMP22 mRNA (p.Gly94Serfs*17). While this is not anticipated to result in nonsense mediated decay, it is expected to result in a truncated PMP22 protein. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature. This variant has been observed to occur de novo in an affected individual tested at Invitae. In addition, a different variant (NM_000304.3:c.281delG) giving rise to a very similar protein effect  (p.Gly94Alafs*17) has been reported in several patients affected with CMT and Dejerine−Sottas syndrome (PMID: 9324088, 11545686, 11835375, 19067730, 26392352), which also suggests that the sequence change observed here is disease-causing. For these reasons, this variant has been classified as Pathogenic. -