Hypertrophic cardiomyopathy_HCM
Gene: ALPK3
Biallelic ALPK3 tv were first identified in children with severe, early-onset CM.
In a discovery cohort of 770 index patients with HCM, 12 (1.56%) were heterozygous for ALPK3tv compared to gnomAD. In a validation cohort of 2047 HCM probands, 32 (1.56%) carried heterozygous ALPK3tv. In comparison with a cohort of genotyped patients with HCM with and without pathogenic sarcomere gene variants, ALPK3tv carriers had a higher prevalence of apical/concentric patterns of hypertrophy.
Truncating variants in ALPK3 are a cause of 1-2% of AD HCM and are associated with a phenotype characterised by extensive fibrosis and a predominantly concentric or apical pattern of left ventricular hypertrophy without left ventricular outflow tract obstruction. Main outcomes = HCM, ICD, LVH, LVSD, SCD.
This group sequenced 4,904 unrelated probands with HCM, DCM, ACM, non-compaction CM, RCM and undefined CM. 1,059 cases with no structural evidence of cardiac disease were used as controls. It should be noted that they selected “LoF” variants so I am assuming this means NMD-predicted variants are what they are referring to when they say “truncated variants”.
All ALPK3 variants in the HCM discovery cohort (n=12) were confirmed with Sanger sequencing. No CNVs were detected. 3 had a VUS in a sarcomere gene, and no other ALPK3 variant. 6 white, 5 South Asian.
In the validation cohort, 24 ALPK3tv were identified in 36 probands. One of these individuals was purported to have a pathogenic variant in MYH7.
There are four recurrent variants: p.Arg1059*, p.Glu1179Argfs*93, p.Trp1563*, and a possible haplotype missense variant linked to p.Arg1059* (p.Arg86Trp).
Age at diagnosis (56+/- 15.9 years) and sex distribution (69% males) of HCM patients with ALPK3tv were similar to sarcomere-negative and higher than sarcomere-positive patients.
Outcome = 14 patients were considered to be at high risk of SCD after their follow ups.
ALPK3tv co-segregated with HCM in 7 available families.
Information on the entire cohort suggests that ALPK3tv are associated with incomplete penetrance until the age of 75 years, when the cumulative percentage of diagnosed carriers increased to >95% among males and 80% among females.Created: 3 Aug 2023, 2 a.m. | Last Modified: 3 Aug 2023, 2 a.m.
Panel Version: 0.175
Mode of inheritance
BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal
Phenotypes
Cardiomyopathy, familial hypertrophic 27 MIM#618052
Publications
Assessed as Strong by ClinGen (ALPK3-HCM)
4 consanguineous families with ALPK3 biallelic pathogenic variants were identified in 2 papers. 3 families are reported in Alomani (2015) (26846950) and 1 in Phelan (2016) with accompanying functional evidence (27106955). ALPK3 knock out mice develop cardiomyopathy (DCM and HCM) Van Sligtenhorst (2012).
A case series of 19 paeditric cardiomyopathy cases with ALPK3 pathogeic variants concluded: Biallelic damaging ALPK3 variants cause pediatric cardiomyopathy manifested by DCM transitioning to hypertrophy, often with poor contractile function. Additional extracardiac features occur in most patients, including musculoskeletal abnormalities and cleft palate. Heterozygous LoF ALPK3 variants are enriched in adults with cardiomyopathy and may contribute to their cardiomyopathy. Adults with ALPK3 LoF variants therefore warrant evaluations for cardiomyopathy.Created: 19 Jun 2020, 11:31 a.m. | Last Modified: 19 Jun 2020, 11:31 a.m.
Panel Version: 0.28
Mode of inheritance
BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal
Phenotypes
hypertrophic cardiomyopathy; dilated cardiomyopathy
Publications
Publications for gene: ALPK3 were set to 26846950; 27106955; 32480058
Gene: alpk3 has been classified as Green List (High Evidence).
Phenotypes for gene: ALPK3 were changed from to Cardiomyopathy, familial hypertrophic 27, MIM# 618052
Publications for gene: ALPK3 were set to
Mode of inheritance for gene: ALPK3 was changed from Unknown to BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal
gene: ALPK3 was added gene: ALPK3 was added to Hypertrophic cardiomyopathy_VCGS. Sources: Expert Review Green,Victorian Clinical Genetics Services Mode of inheritance for gene: ALPK3 was set to Unknown