8-6499930-GTA-TGC

Variant names:

• chr8-6499930-GTA-TGC
• NM_001118887.2:c.*3169_*3171delTACinsGCA

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PVS1_Moderate

The NM_024596.5(MCPH1):​c.2214+1_2214+3delGTAinsTGC variant causes a splice donor, splice region, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MCPH1 NM_024596.5 splice_donor, splice_region, intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.23
• Publications: 0 publications found

Genes affected

ANGPT2 (HGNC:485): (angiopoietin 2) This gene belongs to the angiopoietin family of growth factors. The protein encoded by this gene is an antagonist of angiopoietin 1, and both angiopoietin 1 and angiopoietin 2 are ligands for the endothelial TEK receptor tyrosine kinase. Angiopoietin 2 is upregulated in multiple inflammatory diseases and is implicated in the direct control of inflammation-related signaling pathways. The encoded protein affects angiogenesis during embryogenesis and tumorigenesis, disrupts the vascular remodeling ability of angiopoietin 1, and may induce endothelial cell apoptosis. This gene serves a prognostic biomarker for acute respiratory distress syndrome. [provided by RefSeq, Aug 2020]

MCPH1 (HGNC:6954): (microcephalin 1) This gene encodes a DNA damage response protein. The encoded protein may play a role in G2/M checkpoint arrest via maintenance of inhibitory phosphorylation of cyclin-dependent kinase 1. Mutations in this gene have been associated with primary autosomal recessive microcephaly 1 and premature chromosome condensation syndrome. Alternatively spliced transcript variants have been described. [provided by RefSeq, Feb 2010]

MCPH1 Gene-Disease associations (from GenCC):

• microcephaly 1, primary, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• microcephaly with intellectual disability

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• autosomal recessive primary microcephaly

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary breast carcinoma

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• familial ovarian cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.031100478 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.4, offset of 25, new splice context is: atgGTaaat. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ANGPT2	NM_001118887.2	c.*3169_*3171delTACinsGCA		3_prime_UTR_variant	Exon 9 of 9	ENST00000629816.3	NP_001112359.1
MCPH1	NM_024596.5	c.2214+1_2214+3delGTAinsTGC		splice_donor_variant, splice_region_variant, intron_variant	Intron 12 of 13	ENST00000344683.10	NP_078872.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ANGPT2	ENST00000629816.3	c.*3169_*3171delTACinsGCA		3_prime_UTR_variant	Exon 9 of 9	1	NM_001118887.2	ENSP00000486858.2
MCPH1	ENST00000344683.10	c.2214+1_2214+3delGTAinsTGC		splice_donor_variant, splice_region_variant, intron_variant	Intron 12 of 13	1	NM_024596.5	ENSP00000342924.5

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

May 08, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant has not been reported in the literature in individuals affected with MCPH1-related conditions. Information on the frequency of this variant in the gnomAD database is not available, as this variant may be reported differently in the database. This sequence change affects a splice site in intron 12 of the MCPH1 gene. However, it is currently unclear if variants that occur in this region of the gene cause disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.2

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

hg19: chr8-6357451;