SMS p.Ala36Ala

Variant names:

• chrX-21967251-G-G
• ENST00000404933.7:c.

Your query was ambiguous. Multiple possible variants found:

• chrX-21967252--
• chrX-21967254-G-T
• chrX-21967254-G-C
• chrX-21967254-G-A

Variant summary

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

The ENST00000404933.7(SMS):​c. variant causes a splice donor, intron 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.

• Frequency: Genomes: not found (cov: 21)
• Consequence: SMS ENST00000404933.7 splice_donor, intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.40
• Publications: 0 publications found

Genes affected

SMS (HGNC:11123): (spermine synthase) This gene encodes a protein belonging to the spermidine/spermin synthase family and catalyzes the production of spermine from spermidine. Pseudogenes of this gene are located on chromosomes 1, 5, 6 and X. Mutations in this gene cause an X-linked intellectual disability called Snyder-Robinson Syndrome (SRS). Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2017]

SMS Gene-Disease associations (from GenCC):

• syndromic X-linked intellectual disability Snyder type

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, Orphanet, G2P, ClinGen

ACMG classification

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

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000404933.7. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
There are no transcript annotations for this variant.

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMS	ENST00000404933.7	TSL:1 MANE Select	c.		splice_donor intron	N/A	ENSP00000385746.2	P52788-1
	SMS	ENST00000853889.1		c.		splice_donor intron	N/A	ENSP00000523948.1
	SMS	ENST00000955899.1		c.		splice_donor intron	N/A	ENSP00000625958.1

Frequencies

GnomAD3 genomes Cov.: 21

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 21

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.4

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chrX-21985369;