19-45179387-G-T

Position:

• chr19-45179387-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_212550.5(BLOC1S3):​c.91G>T​(p.Ala31Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000007 in 1,427,720 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A31V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: BLOC1S3 NM_212550.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.41

Genes affected

BLOC1S3 (HGNC:20914): (biogenesis of lysosomal organelles complex 1 subunit 3) This gene encodes a protein that is a component of the BLOC1 multi-subunit protein complex. This complex is necessary for the biogenesis of specialized organelles of the endosomal-lysosomal system, including platelet dense granules and melanosomes. Mutations in this gene cause Hermansky-Pudlak syndrome 8, a disease characterized by lysosomal storage defects, bleeding due to platelet storage pool deficiency, and oculocutaneous albinism. [provided by RefSeq, Jul 2008]

MARK4 (HGNC:13538): (microtubule affinity regulating kinase 4) This gene encodes a member of the microtubule affinity-regulating kinase family. These protein kinases phosphorylate microtubule-associated proteins and regulate the transition between stable and dynamic microtubules. The encoded protein is associated with the centrosome throughout mitosis and may be involved in cell cycle control. Expression of this gene is a potential marker for cancer, and the encoded protein may also play a role in Alzheimer's disease. Pseudogenes of this gene are located on both the short and long arm of chromosome 3. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Dec 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10678238).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BLOC1S3	NM_212550.5	c.91G>T	p.Ala31Ser	missense_variant	2/2	ENST00000433642.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BLOC1S3	ENST00000433642.3	c.91G>T	p.Ala31Ser	missense_variant	2/2	2	NM_212550.5	P1
BLOC1S3	ENST00000587722.1	c.91G>T	p.Ala31Ser	missense_variant	1/1			P1
MARK4	ENST00000587566.5	c.-276-79602G>T		intron_variant		5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.00e-7 AC: 1 AN: 1427720 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 709782

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: 0.00

Gnomad4 OTH exome AF: 0.0000169

GnomAD4 genome Cov.: 32

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 10, 2022

The c.91G>T (p.A31S) alteration is located in exon 2 (coding exon 1) of the BLOC1S3 gene. This alteration results from a G to T substitution at nucleotide position 91, causing the alanine (A) at amino acid position 31 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.41
CADD	Benign	18
DANN	Uncertain	0.98
DEOGEN2	Benign	0.20	T;T
Eigen	Benign	-0.30
Eigen_PC	Benign	-0.19
FATHMM_MKL	Benign	0.60	D
LIST_S2	Benign	0.45	.;T
M_CAP	Benign	0.0059	T
MetaRNN	Benign	0.11	T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.69	N;N
MutationTaster	Benign	1.0	N;N
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-1.1	N;.
REVEL	Benign	0.011
Sift	Benign	0.22	T;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.14	B;B
Vest4		0.13
MutPred		0.20		Gain of phosphorylation at A31 (P = 2e-04);Gain of phosphorylation at A31 (P = 2e-04);
MVP		0.31
MPC		0.87
ClinPred		0.098	T
GERP RS		3.5
Varity_R		0.090
gMVP		0.19

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: rs879252217; hg19: chr19-45682645;