Is LCK p.Pro74= (c.222C>T) pathogenic?

LCK p.Pro74= (c.222C>T) is classified Likely benign in LCK (ClinVar, Single submitter, 1 submitter; last evaluated 2021-07-19). Very rare (popmax 0.000593%, nfe); Associated with severe combined immunodeficiency due to LCK deficiency.

What condition is associated with LCK p.Pro74= (c.222C>T)?

LCK p.Pro74= (c.222C>T) is associated with severe combined immunodeficiency due to LCK deficiency (ClinVar).

How common is LCK p.Pro74= (c.222C>T) in the general population?

LCK p.Pro74= (c.222C>T) is very rare (popmax 0.000593%, nfe) (gnomAD).

How is Combined immunodeficiency due to LCK deficiency inherited?

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

LCK p.Pro74=

c.222C>T · rs768627081 · VCV1589721

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.000593%, nfe)

Conditions

severe combined immunodeficiency due to LCK deficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -0.1	GERP -1, phastCons 0.33
Overall
CADD	10.76	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000593% European (non-Finnish) · 7/1,180,034 alleles

Filtering AF 0.000247% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000159%

Overall 0.00062% 10/1,614,202 alleles · very rare exomes 10/1,461,852 · genomes 0/152,350 · joint denominator

Ancestry group	Frequency	1 in
Remaining individualsnot grpmax-eligible	0.0048%	20,837
European (non-Finnish)grpmax	0.000593%	168,576

Remaining individuals 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: LCK
Protein: p.Pro74=
Coding: c.222C>T
MANE Select: NM_005356
dbSNP: rs768627081
Type: single nucleotide variant
Location: chr1:32275027 (GRCh38)
Gene constraint: LOEUF 0.332 · pLI 1.00 (gnomAD)
Structure: AlphaFold pLDDT 84.12 · 57 PDB
Residue 74: the sh3 domain

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

Disease context

severe combined immunodeficiency due to LCK deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Combined immunodeficiency due to LCK deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

LCK c.631+3G>A Uncertain significance ★★ same condition
LCK p.Ala284Gly Uncertain significance ★★ ⚠ same condition
LCK p.Arg196Pro Uncertain significance ★★ ⚠ same condition
LCK p.Arg219Gln Uncertain significance ★★ ⚠ same condition
LCK p.Arg222His Uncertain significance ★★ ⚠ same condition
LCK p.Arg461His Uncertain significance ★★ ⚠ same condition
LCK p.Asn40Ser Uncertain significance ★★ ⚠ same condition
LCK p.Asp187Gly Uncertain significance ★★ ⚠ 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/lck-p-pro74 (accessed [today's date]).

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