Is SI p.Ser186Pro (c.556T>C) pathogenic?

SI p.Ser186Pro (c.556T>C) is classified Conflicting classifications of pathogenicity in SI (ClinVar, Conflicting submitters, 3 submitters; last evaluated 2026-01-18). AlphaMissense: likely benign (0.0797); Ultra-rare (popmax 0.0733%, amr); Associated with congenital sucrase-isomaltase deficiency.

What condition is associated with SI p.Ser186Pro (c.556T>C)?

SI p.Ser186Pro (c.556T>C) is associated with congenital sucrase-isomaltase deficiency (ClinVar).

How common is SI p.Ser186Pro (c.556T>C) in the general population?

SI p.Ser186Pro (c.556T>C) is ultra-rare (popmax 0.0733%, amr) (gnomAD).

How is Congenital sucrase-isomaltase deficiency inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about SI p.Ser186Pro (c.556T>C)?

AlphaMissense predicts likely benign (score 0.0797) — an in-silico prediction, not a clinical call.

SI p.Ser186Pro

c.556T>C · rs142447888 · VCV344071

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 3 submitters

AlphaMissense

likely benign

0.0797 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.0733%, amr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

congenital sucrase-isomaltase deficiency

Computational evidence

Protein change
AlphaMissense	0.0797	likely benign
REVEL	0.063	moderately benign-leaning
SaProt	LLR -7.90	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 0.99	GERP -1, phastCons 0.12
Regional constraint	o/e 1.10	unconstrained · MANE · 97 kb · p 9.1e-07 · regional, not allelic
Overall
CADD	12.62	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0733% Admixed American · 44/59,990 alleles

Filtering AF 0.0561% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0501%

Overall 0.029% 467/1,612,214 alleles · ultra-rare exomes 415/1,460,020 · genomes 52/152,194 · joint denominator

Ancestry group	Frequency	1 in
Ashkenazi Jewishnot grpmax-eligible	0.189%	528
Admixed Americangrpmax	0.0733%	1,363
Remaining individualsnot grpmax-eligible	0.0384%	2,601
European (non-Finnish)	0.0283%	3,528
Middle Eastern	0.0165%	6,054
African / African-American	0.00933%	10,713
Finnishnot grpmax-eligible	0.00156%	64,016

Ashkenazi Jewish shows a higher raw frequency than the grpmax group above it. gnomAD excludes bottlenecked groups — Finnish, Ashkenazi Jewish, Amish and “Remaining individuals” — from grpmax, because founder effects make their frequencies unrepresentative for filtering. The table is sorted by frequency, so an excluded group can sit above the grpmax row.

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: SI
Protein: p.Ser186Pro
Coding: c.556T>C
MANE Select: NM_001041
dbSNP: rs142447888
Type: single nucleotide variant
Location: chr3:165067419 (GRCh38)
Gene constraint: LOEUF 1.009 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 93.86 · 2 PDB
Residue 186: the 'isomaltase' region

Full SI gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

congenital sucrase-isomaltase deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Congenital sucrase-isomaltase deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Adolescent, Adult, Childhood, Infancy
Prevalence: 1-5 / 10 000 (Europe)

Similar variants

SI c.2426+1G>A Likely pathogenic ★★ same condition
SI c.2893-1G>A Likely pathogenic ★★ same condition
SI c.3099+1G>C Likely pathogenic ★★ same condition
SI c.3521-1G>T Likely pathogenic ★★ same condition
SI c.373+1G>A Likely pathogenic ★★ same condition
SI c.4575+2T>C Likely pathogenic ★★ same condition
SI c.4927-1G>A Likely pathogenic ★★ same condition
SI c.5248-2A>C Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/si-p-ser186pro (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown