NM_018136.5:c.6916_6919delTTAC

Variant names:

• chr1-197102331-TGTAA-T
• rs1064795945
• NM_018136.5:c.6916_6919delTTAC

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_018136.5(ASPM):​c.6916_6919delTTAC​(p.Leu2306SerfsTer20) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,788 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: ASPM NM_018136.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 3.55

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]

ACMG classification

Verdict is Pathogenic. Variant got 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 1-197102331-TGTAA-T is Pathogenic according to our data. Variant chr1-197102331-TGTAA-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 422700.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.6916_6919delTTAC	p.Leu2306SerfsTer20	frameshift_variant	Exon 18 of 28	ENST00000367409.9	NP_060606.3
ASPM	NM_001206846.2	c.4066-6171_4066-6168delTTAC		intron_variant	Intron 17 of 26		NP_001193775.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ASPM	ENST00000367409.9	c.6916_6919delTTAC	p.Leu2306SerfsTer20	frameshift_variant	Exon 18 of 28	1	NM_018136.5	ENSP00000356379.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249968 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135052

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000888

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460788 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 726716

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly 5, primary, autosomal recessive Pathogenic:2

Jun 28, 2017

Geisinger Autism and Developmental Medicine Institute, Geisinger Health System

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing;provider interpretation

This 8 year old female with microcephaly (<2nd percentile) and intellectual disbality was found to carry a maternally inherited variant in the ASPM gene. The p.Leu2306SerfsX20 is absent from population databases. The variant is predicted to cause loss of normal protein function. She also carries a paternally inherited ASPM variant (p.Arg1818Cys), classified as a variant of uncertain significance. While homozygous or compound heterozygous variants in this gene are associated with autosomal recessive primary microcephaly, this patient also carries a maternally-inherited pathogenic variant in KIF11, which is currently thought to be the underlying genetic etiology for her microcephaly and intellectual disability. Individuals with this form of primary microcephaly have been noted to have narrow sloping foreheads; this patient and her mother are both noted to have sloping foreheads with bitemporal narrowing. -

Apr 11, 2023

Genome-Nilou Lab

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Aug 15, 2019

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at a significant frequency in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

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

Publications

LitVar

Other links and lift over

dbSNP: rs1064795945; hg19: chr1-197071461;