8-6431543-C-T

Variant names:

• chr8-6431543-C-T
• rs587783741
• NM_024596.5:c.278C>T

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 6P and 1B. PM1 PM2 PM5 BP4

The NM_024596.5(MCPH1):​c.278C>T​(p.Ala93Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,016 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A93T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MCPH1 NM_024596.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.53
• Publications: 0 publications found

Genes affected

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 5 ACMG points.

• PM1: In a domain BRCT 1 (size 92) in uniprot entity MCPH1_HUMAN there are 9 pathogenic changes around while only 1 benign (90%) in NM_024596.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-6431543-C-A is described in CliVar as Likely_pathogenic. Clinvar id is 158867.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP4: Computational evidence support a benign effect (MetaRNN=0.37161916).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCPH1	NM_024596.5	c.278C>T	p.Ala93Val	missense_variant	Exon 4 of 14	ENST00000344683.10	NP_078872.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCPH1	ENST00000344683.10	c.278C>T	p.Ala93Val	missense_variant	Exon 4 of 14	1	NM_024596.5	ENSP00000342924.5

Frequencies

GnomAD3 genomes AF: 0.00000659 AC: 1 AN: 151784 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461232 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 726950

African (AFR) AF: 0.00 AC: 0 AN: 33456

American (AMR) AF: 0.00 AC: 0 AN: 44716

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

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39622

South Asian (SAS) AF: 0.00 AC: 0 AN: 86198

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111608

Other (OTH) AF: 0.00 AC: 0 AN: 60362

GnomAD4 genome AF: 0.00000659 AC: 1 AN: 151784 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74096

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000242 AC: 1 AN: 41304

American (AMR) AF: 0.00 AC: 0 AN: 15252

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4790

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10502

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67964

Other (OTH) AF: 0.00 AC: 0 AN: 2084

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000113

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Benign	0.0078	T
BayesDel_noAF	Benign	-0.23
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.24	T;.;.
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Benign	0.044	D
MetaRNN	Benign	0.37	T;T;T
MetaSVM	Benign	-0.57	T
MutationAssessor	Uncertain	2.7	M;M;M
PhyloP100		3.5
PrimateAI	Benign	0.45	T
PROVEAN	Benign	-2.1	N;N;N
REVEL	Benign	0.11
Sift	Benign	0.052	T;T;T
Sift4G	Uncertain	0.020	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.32
MutPred		0.25		Loss of disorder (P = 0.0817);Loss of disorder (P = 0.0817);Loss of disorder (P = 0.0817);
MVP		0.73
ClinPred		0.98	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.49
gMVP		0.37
Mutation Taster		=49/51	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs587783741; hg19: chr8-6289064;