7-66988403-C-T

Variant names:

• chr7-66988403-C-T
• NM_016038.4:c.721G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_016038.4(SBDS):​c.721G>A​(p.Asp241Asn) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. D241D) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SBDS NM_016038.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.01
• Publications: 0 publications found

Genes affected

SBDS (HGNC:19440): (SBDS ribosome maturation factor) This gene encodes a highly conserved protein that plays an essential role in ribosome biogenesis. The encoded protein interacts with elongation factor-like GTPase 1 to disassociate eukaryotic initiation factor 6 from the late cytoplasmic pre-60S ribosomal subunit allowing assembly of the 80S subunit. Mutations within this gene are associated with the autosomal recessive disorder Shwachman-Bodian-Diamond syndrome. This gene has a closely linked pseudogene that is distally located. [provided by RefSeq, Jan 2017]

SBDS Gene-Disease associations (from GenCC):

• Shwachman-Diamond syndrome

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• Shwachman-Diamond syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a chain Ribosome maturation protein SBDS (size 248) in uniprot entity SBDS_HUMAN there are 12 pathogenic changes around while only 1 benign (92%) in NM_016038.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3951186).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SBDS	NM_016038.4	c.721G>A	p.Asp241Asn	missense_variant	Exon 5 of 5	ENST00000246868.7	NP_057122.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SBDS	ENST00000246868.7	c.721G>A	p.Asp241Asn	missense_variant	Exon 5 of 5	1	NM_016038.4	ENSP00000246868.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

May 29, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D241N variant (also known as c.721G>A), located in coding exon 5 of the SBDS gene, results from a G to A substitution at nucleotide position 721. The aspartic acid at codon 241 is replaced by asparagine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Uncertain	0.065	T
BayesDel_noAF	Benign	-0.14
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.24	T;T
Eigen	Benign	0.058
Eigen_PC	Uncertain	0.23
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Uncertain	0.22	D
MetaRNN	Benign	0.40	T;T
MetaSVM	Uncertain	0.76	D
MutationAssessor	Benign	2.0	M;.
PhyloP100		7.0
PrimateAI	Uncertain	0.68	T
PROVEAN	Benign	-2.0	N;.
REVEL	Uncertain	0.41
Sift	Benign	0.48	T;.
Sift4G	Benign	0.47	T;T
Polyphen		0.0060	B;.
Vest4		0.57
MutPred		0.17		Loss of helix (P = 0.1706);Loss of helix (P = 0.1706);
MVP		0.99
MPC		0.44
ClinPred		0.78	D
GERP RS		5.0
Varity_R		0.43
gMVP		0.45
Mutation Taster		=49/51	disease causing

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

hg19: chr7-66453390;