NM_018136.5:c.637delA

Variant names:

• chr1-197143614-AT-A
• rs587783258
• NM_018136.5:c.637delA

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.637delA​(p.Ile213TyrfsTer47) 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 1,460,810 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as 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 criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: -0.622
• 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 1-197143614-AT-A is Pathogenic according to our data. Variant chr1-197143614-AT-A is described in ClinVar as Pathogenic. ClinVar VariationId is 157854.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_018136.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ASPM	NM_018136.5	MANE Select	c.637delA	p.Ile213TyrfsTer47	frameshift	Exon 3 of 28	NP_060606.3
	ASPM	NM_001206846.2		c.637delA	p.Ile213TyrfsTer47	frameshift	Exon 3 of 27	NP_001193775.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ASPM	ENST00000367409.9	TSL:1 MANE Select	c.637delA	p.Ile213TyrfsTer47	frameshift	Exon 3 of 28	ENSP00000356379.4
	ASPM	ENST00000294732.11	TSL:1	c.637delA	p.Ile213TyrfsTer47	frameshift	Exon 3 of 27	ENSP00000294732.7
	ASPM	ENST00000680265.1		c.637delA	p.Ile213TyrfsTer47	frameshift	Exon 3 of 29	ENSP00000505384.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460810 Hom.: 0 Cov.: 36 AF XY: 0.00000138 AC XY: 1 AN XY: 726754

African (AFR) AF: 0.0000597 AC: 2 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52548

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111846

Other (OTH) AF: 0.00 AC: 0 AN: 60384

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000936 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly 5, primary, autosomal recessive Pathogenic:3

Sep 12, 2025

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is classified as Pathogenic. Evidence in support of pathogenic classification: Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction); Variant is present in gnomAD <0.01 for a recessive condition (v4: 2 heterozygote(s), 0 homozygote(s)); This variant has strong previous evidence of pathogenicity in unrelated individuals. It has been classified as pathogenic by clinical laboratories in ClinVar; Other NMD-predicted variant(s) comparable to the one identified in this case have very strong previous evidence for pathogenicity (DECIPHER). Additional information: This variant is homozygous; This gene is associated with autosomal recessive disease; Loss of function is a known mechanism of disease in this gene and is associated with microcephaly 5, primary (MIM#608716); This variant has been shown to be both maternally and paternally inherited (biallelic) (by trio analysis).

Jun 24, 2014

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Apr 11, 2023

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:3

Dec 05, 2024

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 significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 30221345, 23611254)

May 28, 2015

Clinical Genetics and Genomics, Karolinska University Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Mar 01, 2017

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.62
Mutation Taster		=4/196	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: rs587783258; hg19: chr1-197112744;