CRYBB1

Chr 22ADAR

crystallin beta B1

Also known as: CATCN3, CTRCT17

NCBI Gene: 1414 ENSG00000100122 UniProt: P53674

Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N- and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, undergoes extensive cleavage at its N-terminal extension during lens maturation. It is also a member of a gene cluster with beta-A4, beta-B2, and beta-B3. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Cataract 17, multiple typesMIM #611544

ADAR

152

ClinVar variants

Pathogenic / LP

0.00

pLI score

Active trials

Clinical Summary— CRYBB1

⚡

Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

36 Pathogenic / Likely Pathogenic· 78 VUS of 152 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.

1.00LOEUF

pLI 0.001

Z-score 1.58

OE 0.53 (0.30–1.00)

Tolerant

Typical tolerance to LoF variation

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.

0.35Z-score

OE missense 0.92 (0.81–1.05)

156 obs / 168.8 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.

LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.53 (0.30–1.00)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.92 (0.81–1.05)

0≤0.61.4

Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.1.01

0≤1.21.6

LoF obs/exp: 7 / 13.2Missense obs/exp: 156 / 168.8Syn Z: -0.07