Genetic Variant UPB1:c.105-2A>C (chr22-24500105-A-C) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_016327.3(UPB1):c.105-2A>C variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.000000684 in 1,461,836 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

UPB1
NM_016327.3 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 5.83

Publications

0 publications found

Variant links:

Genes affected

UPB1 (HGNC:16297): (beta-ureidopropionase 1) This gene encodes a protein that belongs to the CN hydrolase family. Beta-ureidopropionase catalyzes the last step in the pyrimidine degradation pathway. The pyrimidine bases uracil and thymine are degraded via the consecutive action of dihydropyrimidine dehydrogenase (DHPDH), dihydropyrimidinase (DHP) and beta-ureidopropionase (UP) to beta-alanine and beta-aminoisobutyric acid, respectively. UP deficiencies are associated with N-carbamyl-beta-amino aciduria and may lead to abnormalities in neurological activity. [provided by RefSeq, Jul 2008]

UPB1 Gene-Disease associations (from GenCC):

beta-ureidopropionase deficiency
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae)

UPB1 links:

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ACMG classification

Classification was made for transcript

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

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5.2, offset of 4, new splice context is: tttcctgcccatctcggaAGctt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
UPB1	NM_016327.3 link	c.105-2A>C		splice_acceptor_variant, intron_variant	Intron 1 of 9	ENST00000326010.10	NP_057411.1	Q9UBR1A0A024R1H3B3KNC1

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein	UniProt
UPB1	ENST00000326010.10 link	c.105-2A>C	splice_acceptor_variant, intron_variant	Intron 1 of 9	1	NM_016327.3	ENSP00000324343.5	Q9UBR1
UPB1	ENST00000382760.2 link	c.105-2A>C	splice_acceptor_variant, intron_variant	Intron 1 of 3	5		ENSP00000372208.2	Q6AHZ8
UPB1	ENST00000415388.5 link	n.105-2021A>C	intron_variant	Intron 1 of 8	5		ENSP00000400684.1	F8WC94

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461836

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727224

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53368

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112006

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Uncertain

0.10

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

0.96

Eigen_PC

Pathogenic

0.77

FATHMM_MKL

Uncertain

0.97

PhyloP100

5.8

GERP RS

4.9

Mutation Taster

=3/97

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.92

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.92

Position offset: 2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over