21-36759812-G-A

Position:

• chr21-36759812-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP6 BS1

The NM_001352514.2(HLCS):​c.2151C>T​(p.Asn717Asn) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000113 in 1,612,826 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00012 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00011 (0 hom.)
• Consequence: HLCS NM_001352514.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:3
• Conservation: PhyloP100: 0.556

Genes affected

HLCS (HGNC:4976): (holocarboxylase synthetase) This gene encodes an enzyme that catalyzes the binding of biotin to carboxylases and histones. The protein plays an important role in gluconeogenesis, fatty acid synthesis and branched chain amino acid catabolism. Defects in this gene are the cause of holocarboxylase synthetase deficiency. Multiple alternatively spliced variants, encoding the same protein, have been identified.[provided by RefSeq, Jun 2011]

HLCS (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 21-36759812-G-A is Benign according to our data. Variant chr21-36759812-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 137545.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Benign=2}.
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000118 (18/152232) while in subpopulation EAS AF= 0.00251 (13/5182). AF 95% confidence interval is 0.00148. There are 0 homozygotes in gnomad4. There are 9 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HLCS	NM_001352514.2	c.2151C>T	p.Asn717Asn	synonymous_variant	9/11	ENST00000674895.3	NP_001339443.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HLCS	ENST00000674895.3	c.2151C>T	p.Asn717Asn	synonymous_variant	9/11		NM_001352514.2	ENSP00000502087.2

Frequencies

GnomAD3 genomes AF: 0.000118 AC: 18 AN: 152114 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00250

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.000957

GnomAD3 exomes AF: 0.000302 AC: 76 AN: 251488 Hom.: 0 AF XY: 0.000302 AC XY: 41 AN XY: 135920

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00397

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000112 AC: 164 AN: 1460594 Hom.: 0 Cov.: 29 AF XY: 0.000107 AC XY: 78 AN XY: 726714

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00285

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000720

Gnomad4 OTH exome AF: 0.000696

GnomAD4 genome AF: 0.000118 AC: 18 AN: 152232 Hom.: 0 Cov.: 33 AF XY: 0.000121 AC XY: 9 AN XY: 74434

Gnomad4 AFR AF: 0.0000482

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00251

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.000947

Alfa AF: 0.0000508 Hom.: 0

Bravo AF: 0.000174

Asia WGS AF: 0.00144 AC: 5 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Holocarboxylase synthetase deficiency Uncertain:1 Benign:1

Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 30, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 27, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

not specified Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Apr 09, 2014

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

HLCS-related disorder Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 03, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.48
CADD	Benign	13
DANN	Benign	0.87

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.21		Position offset: -15

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs148709879; hg19: chr21-38132113;