1-113904937-C-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP3 BS1_Supporting BS2

The ENST00000256658.8(AP4B1):c.-77+5G>A variant causes a splice donor 5th base, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00227 in 533,082 control chromosomes in the GnomAD database, including 21 homozygotes. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0019 (12 hom., cov: 33)
  • Exomes 𝑓: 0.0024 (9 hom.)
• Consequence: AP4B1 ENST00000256658.8 splice_donor_5th_base, intron
• Scores: Splicing: ADA: 0.9990
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.96

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]

DCLRE1B (HGNC:17641): (DNA cross-link repair 1B) DNA interstrand cross-links prevent strand separation, thereby physically blocking transcription, replication, and segregation of DNA. DCLRE1B is one of several evolutionarily conserved genes involved in repair of interstrand cross-links (Dronkert et al., 2000 [PubMed 10848582]).[supplied by OMIM, Mar 2008]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.00185 (282/152106) while in subpopulation EAS AF= 0.0491 (251/5114). AF 95% confidence interval is 0.0441. There are 12 homozygotes in gnomad4. There are 144 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High Homozygotes in GnomAd at 12 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
AP4B1	XM_047438847.1	c.-93G>A		5_prime_UTR_variant	1/11
AP4B1	NM_001253853.3	c.-246+5G>A		splice_donor_5th_base_variant, intron_variant
DCLRE1B	NM_001319947.2	c.-331+229C>T		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AP4B1	ENST00000256658.8	c.-77+5G>A		splice_donor_5th_base_variant, intron_variant		1		P1
AP4B1	ENST00000369571.3	c.-93G>A		5_prime_UTR_variant	1/11	3		P1
AP4B1	ENST00000369564.6	c.-77+5G>A		splice_donor_5th_base_variant, intron_variant		5

Frequencies

GnomAD3 genomes AF: 0.00186 AC: 282 AN: 151986 Hom.: 12 Cov.: 33

Gnomad AFR AF: 0.000314

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000524

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.0490

Gnomad SAS AF: 0.000830

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00144

GnomAD4 exome AF: 0.00243 AC: 927 AN: 380976 Hom.: 9 Cov.: 3 AF XY: 0.00229 AC XY: 465 AN XY: 202718

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0328

Gnomad4 SAS exome AF: 0.00108

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000266

Gnomad4 OTH exome AF: 0.00293

GnomAD4 genome AF: 0.00185 AC: 282 AN: 152106 Hom.: 12 Cov.: 33 AF XY: 0.00194 AC XY: 144 AN XY: 74346

Gnomad4 AFR AF: 0.000313

Gnomad4 AMR AF: 0.000523

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.0491

Gnomad4 SAS AF: 0.000831

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00142

Alfa AF: 0.000818 Hom.: 0

Bravo AF: 0.00241

Asia WGS AF: 0.0130 AC: 46 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

Oct 02, 2017

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.72
Cadd	Benign	15
Dann	Benign	0.85

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.87
SpliceAI score (max)		0.12		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: rs28364563; hg19: chr1-114447559;