X-154097642-CGCGGCGGCG-CGCGGCGGCGGCG
Variant summary
Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP6_Very_StrongBS2_Supporting
The NM_001110792.2(MECP2):c.21_23dupCGC(p.Ala8dup) variant causes a disruptive inframe insertion change. The variant allele was found at a frequency of 0.0002 in 1,024,821 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 36 hemizygotes in GnomAD. Variant has been reported in ClinVar as Benign (★★★).
Frequency
Consequence
NM_001110792.2 disruptive_inframe_insertion
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -9 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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MECP2 | NM_001110792.2 | c.21_23dupCGC | p.Ala8dup | disruptive_inframe_insertion | Exon 1 of 3 | ENST00000453960.7 | NP_001104262.1 | |
MECP2 | NM_004992.4 | c.-140_-138dupCGC | 5_prime_UTR_variant | Exon 1 of 4 | ENST00000303391.11 | NP_004983.1 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
MECP2 | ENST00000453960.7 | c.21_23dupCGC | p.Ala8dup | disruptive_inframe_insertion | Exon 1 of 3 | 1 | NM_001110792.2 | ENSP00000395535.2 | ||
MECP2 | ENST00000303391.11 | c.-140_-138dupCGC | 5_prime_UTR_variant | Exon 1 of 4 | 1 | NM_004992.4 | ENSP00000301948.6 |
Frequencies
GnomAD3 genomes AF: 0.000160 AC: 17AN: 106552Hom.: 0 Cov.: 21 AF XY: 0.0000663 AC XY: 2AN XY: 30188
GnomAD3 exomes AF: 0.0000333 AC: 2AN: 59976Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 15452
GnomAD4 exome AF: 0.000205 AC: 188AN: 918269Hom.: 0 Cov.: 26 AF XY: 0.000119 AC XY: 34AN XY: 284887
GnomAD4 genome AF: 0.000160 AC: 17AN: 106552Hom.: 0 Cov.: 21 AF XY: 0.0000663 AC XY: 2AN XY: 30188
ClinVar
Submissions by phenotype
not provided Uncertain:3Benign:2
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MECP2: BS2 -
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The c.23_24insCGC (aka c.21_23dupCGC) variant results in the duplication of a single Alanine residue in a poorly conserved region of the MECP2_e1 transcript. Although c.21_23dupCGC has not been published to our knowledge, it is reported in a gene specific mutation database as a variant of unknown pathogenicity. Additionally, a duplication of two Alanine residues in this region of the protein has been reported as a benign polymorphism because it was identified in a female with Rett syndrome and her unaffected mother in one family and did not co-segregate with intellectual disability in another family (Evans et al., 2005; Quenard et al., 2006). However, other variations in the number of Alanine or Glycine repeats in this region of the protein were found in approximately 1% of females with intellectual disability but a significantly smaller percentage of controls, so the authors suggested these variants may be associated with an increased risk for intellectual disability (Harvey et al., 2007). This variant has been observed to be inherited from an apparently unaffected mother. The variant is found in MECP2 panel(s). -
not specified Uncertain:3
Variant summary: MECP2 c.-140_-138dupCGC is located in the untranslated mRNA region upstream of the initiation codon in transcript NM_004992. The variant allele was found at a frequency of 3.3e-05 in 59976 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.-140_-138dupCGC in individuals affected with Rett Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Two other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory cited the variant as benign and one laboratory cited the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
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Rett syndrome Benign:2
The allele frequency of the c.-140_-138dup variant in MECP2 (NM_004992.3) is over 0.01% in South Asian, European (non-Finnish), and Latino/Admixed american sub populations in gnomAD, which is high enough to meet the BS1 criteria based on thresholds defined by the ClinGen Rett/Angelman-like Expert Panel for Rett/AS-like conditions (BS1). The c.-140_-138dup variant in MECP2 is observed in at least 2 unaffected individuals (Invitae internal database) (BS2). The c.-140_-138dup variant is found in at least 3 patients with an alternate molecular basis of disease (Invitae internal database) (BP5). In summary the c.-140_-138dup variant in MECP2 is classified as a benign variant based on the ACMG/AMP criteria (BS1, BS2, BP5). -
This variant has been collected from RettBASE and curated to current modified ACMG/AMP criteria.Based on the classification scheme defined by the ClinGen Rett/Angelman-like Expert Panel for Rett/AS-like Disorders Specifications to the ACMG/AMP Variant Interpretation Guidelines VCEP 2.0, this variant is classified as benign. At least the following criteria are met: The allele frequency of this variant in at least one population in gnomAD v3 is higher than the 0.03% threshold defined by the ClinGen Rett/Angelman-like Expert Panel for Rett/AS-like Disorders VCEP 2.0 (BA1). -
Severe neonatal-onset encephalopathy with microcephaly Benign:1
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Inborn genetic diseases Benign:1
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
MECP2-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at