22-26451980-C-T

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 2P and 10B. PM2 BP4_Strong BP6_Moderate BS1

The NM_022081.6(HPS4):c.*1253G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00124 in 175,478 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.0015 (0 hom., cov: 30)
  • Exomes 𝑓: 0.00018 (0 hom.)
• Consequence: HPS4 NM_022081.6 3_prime_UTR
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.525

Genes affected

HPS4 (HGNC:15844): (HPS4 biogenesis of lysosomal organelles complex 3 subunit 2) This gene encodes a protein component of biogenesis of lysosome-related organelles complexes (BLOC). BLOC complexes are important for the formation of endosomal-lysosomal organelles such as melanosomes and platelet dense granules. Mutations in this gene result in subtype 4 of Hermansky-Pudlak syndrome, a form of albinism. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2012]

ACMG classification

Verdict is Benign. Variant got -8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).
• BP6: Variant 22-26451980-C-T is Benign according to our data. Variant chr22-26451980-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 340971.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00154 (210/136450) while in subpopulation AFR AF= 0.00494 (187/37834). AF 95% confidence interval is 0.00436. There are 0 homozygotes in gnomad4. There are 85 alleles in male gnomad4 subpopulation. Median coverage is 30. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HPS4	NM_022081.6	c.*1253G>A		3_prime_UTR_variant	14/14	ENST00000398145.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HPS4	ENST00000398145.7	c.*1253G>A		3_prime_UTR_variant	14/14	1	NM_022081.6	P2

Frequencies

GnomAD3 genomes AF: 0.00154 AC: 210 AN: 136342 Hom.: 0 Cov.: 30

Gnomad AFR AF: 0.00496

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000845

Gnomad ASJ AF: 0.000301

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00680

Gnomad NFE AF: 0.000127

Gnomad OTH AF: 0.000563

GnomAD4 exome AF: 0.000179 AC: 7 AN: 39028 Hom.: 0 Cov.: 0 AF XY: 0.000133 AC XY: 3 AN XY: 22516

Gnomad4 AFR exome AF: 0.00327

Gnomad4 AMR exome AF: 0.000534

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: 0.0000806

Gnomad4 OTH exome AF: 0.00123

GnomAD4 genome AF: 0.00154 AC: 210 AN: 136450 Hom.: 0 Cov.: 30 AF XY: 0.00130 AC XY: 85 AN XY: 65400

Gnomad4 AFR AF: 0.00494

Gnomad4 AMR AF: 0.000844

Gnomad4 ASJ AF: 0.000301

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000127

Gnomad4 OTH AF: 0.000556

Alfa AF: 0.00139 Hom.: 0

Bravo AF: 0.00161

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hermansky-Pudlak syndrome 4 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
Cadd	Benign	5.0
Dann	Benign	0.83

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

Publications

LitVar

Other links and lift over

dbSNP: rs534586940; hg19: chr22-26847946;