| Publication (year) | PMID | Family structure / consanguinity | Variant(s) (HGVS c. and p.) | Variant type | Zygosity | ACMG classification | Key genotype-phenotype notes (1 line) | Notable population data |
|---|---|---|---|---|---|---|---|---|
| Thomas et al. (2014/2015) | 25439728 | 3 unrelated consanguineous families; 7 affected individuals total (5F, 2M) (pqac-00000027, pqac-00000030) | Family 1: c.2596C>T, p.Gln866*; Family 2: c.1108+1181_2108-2342del, p.Val369_Leu702del; Family 3: c.1894+1G>A, splice effect reported as p.Ala603_Gly632del / part-PX-domain deletion in retrieved text (pqac-00000030, pqac-00000016) | Nonsense; multiexon deletion; splice-site (pqac-00000030) | Homozygous in each family (pqac-00000030) | Not stated in retrieved text | Severe intellectual disability, hypotonia, delayed milestones, ataxia, progressive cerebellar atrophy (5/7), pontine thinning (4/7), hearing loss (5/7); mutations predicted to disrupt/remove PX and/or RGS domains (pqac-00000030, pqac-00000016) | Not stated in retrieved text |
| Akizu et al. (2015) | not in retrieved text | Initial cohort of 96 families with childhood-onset recessive cerebellar atrophy; 81 consanguineous families; identified 16 patients from 8 families with truncating SNX14 variants; later summary table covered 22 affected individuals from 12 families (pqac-00000024, pqac-00000026, pqac-00000029, pqac-00000031) | Specific family-level HGVS not fully enumerated in retrieved text; study summary reports truncating / loss-of-function biallelic SNX14 variants including recurrent founder p.Arg378* allele in 3 families (pqac-00000024, pqac-00000031) | Truncating loss-of-function variants (nonsense/frameshift/splice not individually resolved in retrieved text) (pqac-00000024, pqac-00000029) | Biallelic; predominantly homozygous in consanguineous families (pqac-00000024, pqac-00000031) | Not stated in retrieved text | Distinct syndromic cerebellar atrophy with coarse facies in all, onset birth-1 year, hypotonia, seizures in ~50% by age 2, hearing loss in ~1/3; patient cells showed engorged lysosomes and slower autophagosome clearance (pqac-00000024, pqac-00000025, pqac-00000026) | Founder allele p.Arg378* on a 1.5 Mb haplotype in 3 families; SNX14 accounted for ~10% of families in this cohort (pqac-00000031) |
| Maia et al. (2020) | not in retrieved text | First reported non-consanguineous SCAR20 family; 2 affected siblings (pqac-00000003, pqac-00000038) | c.1195C>T, p.Arg399* plus complex rearrangement c.[612+3028_698-2759del;698-2758_698-516inv;698-515_1171+1366delinsAG] (pqac-00000003, pqac-00000038) | Nonsense + complex genomic rearrangement (2 deletions, inversion, insertion) (pqac-00000003, pqac-00000038) | Compound heterozygous (pqac-00000003) | Not stated in retrieved text | Extended phenotype with dystonia and stereotypies in addition to classic SCAR20 features; MRI showed diffuse cerebellar and pontine atrophy (pqac-00000003, pqac-00000038) | Not stated in retrieved text |
| Kim et al. (2021) | not in retrieved text | Korean family with 2 affected siblings; parents heterozygous carriers; report notes prior cases mostly from consanguineous families (pqac-00000001, pqac-00000036) | c.2746-2A>G (splice acceptor) (pqac-00000001, pqac-00000036) | Splice-site loss-of-function (pqac-00000001, pqac-00000036) | Homozygous in both siblings (pqac-00000001, pqac-00000036) | Pathogenic (reported in summary of retrieved evidence) (pqac-00000001) | Severe developmental delay with progressive cerebellar atrophy in older sibling; younger sibling had initially intact cerebellum, illustrating age-dependent imaging progression (pqac-00000001, pqac-00000036) | gnomAD allele frequency reported as 1/245460 for c.2746-2A>G (pqac-00000001) |
| Levchenko et al. (2023) | not in retrieved text | 2 sisters from a consanguineous family (pqac-00000000, pqac-00000032) | c.462-589A>G causing pseudo-exon inclusion; protein consequence p.Asp155Valfs*8 (pqac-00000000, pqac-00000032) | Deep intronic splice-altering variant causing frameshift / premature stop (pqac-00000000, pqac-00000032) | Homozygous (pqac-00000000, pqac-00000032) | Not stated in retrieved text | First deep intronic SNX14 case; diagnosis required trio WGS after extensive diagnostic workup and expanded SCAR20 mutational spectrum beyond coding/canonical splice variants (pqac-00000000, pqac-00000032) | Retrieved text notes 28 pathogenic/likely pathogenic SNX14 variants in ClinVar and >36 patients from 19 families, but no variant-specific population AF (pqac-00000000, pqac-00000032) |
| Shao et al. (2024) | not in retrieved text | Family with 2 affected children (siblings) and unaffected carrier parents; prenatal ultrasound abnormalities prompted evaluation (pqac-00000005, pqac-00000035) | c.712A>T, p.Arg238Ter and c.2744A>T, p.Gln915Leu (pqac-00000005, pqac-00000035) | Nonsense + missense (pqac-00000005) | Compound heterozygous (pqac-00000005) | p.Arg238Ter: pathogenic; p.Gln915Leu: VUS (ACMG, as stated) (pqac-00000005) | In vitro experiments showed both variants reduced SNX14 expression; phenotype included prenatal skeletal/craniofacial abnormalities, postnatal developmental delay and hypotonia (pqac-00000005, pqac-00000035) | Not stated in retrieved text |


*Table: This table summarizes reported SNX14 disease-causing variants and key genetic evidence for Lichtenstein-Knorr syndrome/SCAR20 from the retrieved literature. It highlights variant class, zygosity, family structure, and notable genotype-phenotype or population observations useful for curation.*