Genetic Variant AP4B1:c.618-2A>C (chr1-113900402-T-G) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_001253852.3(AP4B1):c.618-2A>C variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.000000684 in 1,461,250 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

AP4B1
NM_001253852.3 splice_acceptor, intron

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 6.93

Publications

0 publications found

Variant links:

Genes affected

AP4B1 (HGNC:572): (adaptor related protein complex 4 subunit beta 1) This gene encodes a subunit of a heterotetrameric adapter-like complex 4 that is involved in targeting proteins from the trans-Golgi network to the endosomal-lysosomal system. Mutations in this gene are associated with cerebral palsy spastic quadriplegic type 5 (CPSQ5) disorder. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2011]

AP4B1 links:

AP4B1-AS1 (HGNC:44114): (AP4B1 antisense RNA 1)

AP4B1-AS1 links:

Genome browser will be placed here

new If you want to explore the variant's impact on the transcript NM_001253852.3, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001253852.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
AP4B1	NM_001253852.3	MANE Select	c.618-2A>C	splice_acceptor intron	N/A	NP_001240781.1	Q9Y6B7-1
AP4B1	NM_001438373.1		c.618-2A>C	splice_acceptor intron	N/A	NP_001425302.1
AP4B1	NM_006594.5		c.618-2A>C	splice_acceptor intron	N/A	NP_006585.2	Q9Y6B7-1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
AP4B1	ENST00000369569.6	TSL:1 MANE Select	c.618-2A>C	splice_acceptor intron	N/A	ENSP00000358582.1	Q9Y6B7-1
AP4B1	ENST00000256658.8	TSL:1	c.618-2A>C	splice_acceptor intron	N/A	ENSP00000256658.4	Q9Y6B7-1
AP4B1	ENST00000863127.1		c.618-2A>C	splice_acceptor intron	N/A	ENSP00000533186.1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461250

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726952

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33458

American (AMR)

AF:

0.00

AC:

AN:

44434

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39684

South Asian (SAS)

AF:

0.00

AC:

AN:

86174

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53346

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111888

Other (OTH)

AF:

0.00

AC:

AN:

60378

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Uncertain

0.050

CADD

Uncertain

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

0.97

Eigen_PC

Pathogenic

0.77

FATHMM_MKL

Pathogenic

1.0

PhyloP100

6.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.41

Position offset: -30

DS_AL_spliceai

0.99

Position offset: -2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over