NM_018136.5:c.3960_3961insA

Variant names:

• chr1-197117893-C-CT
• rs759632528
• NM_018136.5:c.3960_3961insA

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_018136.5(ASPM):​c.3960_3961insA​(p.Val1321SerfsTer29) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,120 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. L1320L) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: ASPM NM_018136.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: -0.196
• Publications: 1 publications found

Genes affected

ASPM (HGNC:19048): (assembly factor for spindle microtubules) This gene is the human ortholog of the Drosophila melanogaster 'abnormal spindle' gene (asp), which is essential for normal mitotic spindle function in embryonic neuroblasts. Studies in mouse also suggest a role of this gene in mitotic spindle regulation, with a preferential role in regulating neurogenesis. Mutations in this gene are associated with microcephaly primary type 5. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, May 2011]

ASPM Gene-Disease associations (from GenCC):

• microcephaly 5, primary, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• autosomal recessive primary microcephaly

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-197117893-C-CT is Pathogenic according to our data. Variant chr1-197117893-C-CT is described in ClinVar as [Pathogenic]. Clinvar id is 210355.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ASPM	NM_018136.5	c.3960_3961insA	p.Val1321SerfsTer29	frameshift_variant	Exon 17 of 28	ENST00000367409.9	NP_060606.3
ASPM	NM_001206846.2	c.3960_3961insA	p.Val1321SerfsTer29	frameshift_variant	Exon 17 of 27		NP_001193775.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ASPM	ENST00000367409.9	c.3960_3961insA	p.Val1321SerfsTer29	frameshift_variant	Exon 17 of 28	1	NM_018136.5	ENSP00000356379.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000120 AC: 3 AN: 250772 AF XY: 0.0000221

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000868

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461120 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 726922

African (AFR) AF: 0.00 AC: 0 AN: 33446

American (AMR) AF: 0.0000671 AC: 3 AN: 44704

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26118

East Asian (EAS) AF: 0.00 AC: 0 AN: 39642

South Asian (SAS) AF: 0.00 AC: 0 AN: 86244

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111436

Other (OTH) AF: 0.00 AC: 0 AN: 60370

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly 5, primary, autosomal recessive Pathogenic:1

Feb 08, 2013

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Jul 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Val1321Serfs*29) in the ASPM gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ASPM are known to be pathogenic (PMID: 19028728, 23611254). This variant is present in population databases (rs759632528, gnomAD 0.009%). This premature translational stop signal has been observed in individual(s) with ASPM-related conditions (PMID: 23611254). ClinVar contains an entry for this variant (Variation ID: 210355). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.20
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs759632528; hg19: chr1-197087023;