chr22-26457947-TG-T

Variant names:

• chr22-26457947-TG-T
• rs281865099
• NM_022081.6:c.1866delC

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_022081.6(HPS4):​c.1866delC​(p.Thr623ProfsTer13) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 35)
• Consequence: HPS4 NM_022081.6 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.367
• Publications: 2 publications found

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]

HPS4 Gene-Disease associations (from GenCC):

• Hermansky-Pudlak syndrome 4

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, ClinGen, Labcorp Genetics (formerly Invitae), Ambry Genetics
• Hermansky-Pudlak syndrome with pulmonary fibrosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HPS4	NM_022081.6	c.1866delC	p.Thr623ProfsTer13	frameshift_variant	Exon 13 of 14	ENST00000398145.7	NP_071364.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HPS4	ENST00000398145.7	c.1866delC	p.Thr623ProfsTer13	frameshift_variant	Exon 13 of 14	1	NM_022081.6	ENSP00000381213.2

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome Cov.: 37

GnomAD4 genome Cov.: 35

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.37
Mutation Taster		=0/200	disease causing (ClinVar)

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: rs281865099; hg19: chr22-26853913;