4-112647384-A-T

Variant names:

• chr4-112647384-A-T
• rs1060499762
• NM_016648.4:c.832A>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_016648.4(LARP7):​c.832A>T​(p.Lys278*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,844 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 pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LARP7 NM_016648.4 stop_gained
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 2.02
• Publications: 0 publications found

Genes affected

LARP7 (HGNC:24912): (La ribonucleoprotein 7, transcriptional regulator) This gene encodes a protein which is found in the 7SK snRNP (small nuclear ribonucleoprotein). This snRNP complex inhibits a cyclin-dependent kinase, positive transcription elongation factor b, which is required for paused RNA polymerase II at a promoter to begin transcription elongation. A pseudogene of this gene is located on chromosome 3. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2012]

MIR302CHG (HGNC:41070): (miR-302/367 cluster host gene)

ACMG classification

Our verdict: Pathogenic. The variant received 18 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
• PP5: Variant 4-112647384-A-T is Pathogenic according to our data. Variant chr4-112647384-A-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 402189.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LARP7	NM_016648.4	c.832A>T	p.Lys278*	stop_gained	Exon 7 of 13	ENST00000344442.10	NP_057732.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LARP7	ENST00000344442.10	c.832A>T	p.Lys278*	stop_gained	Exon 7 of 13	2	NM_016648.4	ENSP00000344950.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461844 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727220

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111992

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephalic primordial dwarfism, Alazami type Pathogenic:1

May 02, 2023

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

The homozygous p.Lys285Ter variant in LARP7 was identified by our study in two siblings with Alazami syndrome. The p.Lys285Ter variant in LARP7 has been previously reported in two unrelated individuals with Alazami syndrome (PMID: 26539891, PMID: 30426380) and segregated with disease in 2 affected relatives in one family (PMID: 30426380). These two previously reported unrelated individuals were homozygotes, which increases the likelihood that the p.Lys285Ter variant is pathogenic. This variant has also been reported in ClinVar (Variation ID: 402189) and has been interpreted as likely pathogenic by the Lupski Lab (Baylor-Hopkins CMG, Baylor College of Medicine). This variant was absent from large population studies. This nonsense variant leads to a premature termination codon at position 285, which is predicted to lead to a truncated or absent protein. Loss of function of the LARP7 gene is strongly associated to autosomal recessive Alazami syndrome. In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic for autosomal recessive Alazami syndrome. ACMG/AMP Criteria applied: PVS1_Strong, PM2_Supporting, PM3 (Richards 2015).

Abnormal brain morphology Pathogenic:1

Lupski Lab, Baylor-Hopkins CMG, Baylor College of Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	36
DANN	Uncertain	0.99
DEOGEN2	Benign	0.0	.;.;.;.
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Benign	0.000010	N
LIST_S2	Benign	0.0	.;.;.;.
MetaRNN	Benign	0.0	.;.;.;.
MutationAssessor	Benign	0.0	.;.;.;.
PhyloP100		2.0
PROVEAN	Benign	0.0	.;.;.;.
REVEL	Benign	0.0
Sift	Pathogenic	0.0	.;.;.;.
Sift4G	Pathogenic	0.0	.;.;.;.
Vest4		0.77
ClinPred		1.0	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1060499762; hg19: chr4-113568540;