rs1019204290

Positions:

• chr1-113902633-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP5 BP4

The NM_001253852.3(AP4B1):​c.338+5G>A variant causes a splice region, intron change. The variant allele was found at a frequency of 0.00000274 in 1,460,100 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: AP4B1 NM_001253852.3 splice_region, intron
• Scores: Splicing: ADA: 0.9489
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 4.82

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-113902633-C-T is Pathogenic according to our data. Variant chr1-113902633-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 434229.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}.
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.28). . Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
AP4B1	NM_001253852.3	c.338+5G>A		splice_region_variant, intron_variant		ENST00000369569.6	NP_001240781.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
AP4B1	ENST00000369569.6	c.338+5G>A		splice_region_variant, intron_variant		1	NM_001253852.3	ENSP00000358582.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460100 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726398

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: 0.00000270

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

Bravo AF: 0.0000113

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary spastic paraplegia 47 Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 01, 2022	In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. ClinVar contains an entry for this variant (Variation ID: 434229). This variant has not been reported in the literature in individuals affected with AP4B1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 3 of the AP4B1 gene. It does not directly change the encoded amino acid sequence of the AP4B1 protein. It affects a nucleotide within the consensus splice site. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Nov 02, 2015	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.28
CADD	Uncertain	24
DANN	Benign	0.93

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.95
dbscSNV1_RF	Pathogenic	0.85
SpliceAI score (max)		0.030		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: rs1019204290; hg19: chr1-114445255;