Table 2.
Clinical features of subjects with β MHC mutations classified according to genotype and affected domain of β MHC
| Mutation* | Number affected | Age at diagnosis (years) | Age at death† (years) | Deaths age⩽60/deaths age⩽40 | Myectomy or NSRT |
ECG Estes score | MLVWT (mm) |
Echo LVH score | LVEDD (mm) |
LA (mm) |
| Active site (0) | ||||||||||
| Ala196Thr | 3 | 42 (4) | 54 | 1/0 | 0 | 5 (3) | 27 (4) | 7 (4) | 51 (6) | 54 (4) |
| Pro211Leu | 3 | 33 (13) | NA | 0/0 | 0 | 2 (4) | 13 (10) | 1 (1) | 41 (4) | 35 (7) |
| Active site (+) | ||||||||||
| Arg249Gln | 3 | 54 (20) | 77 | 0/0 | 1 | 3 (2) | 24 (7) | 6 (1) | 45 (6) | 40 (12) |
| Arg453Cys | 2 | 66 (31) | NA | 0/0 | 0 | 4 | 23 | 4 | 45 | 62 |
| Actin binding (0) | ||||||||||
| Val404Leu | 12 | 46 (20) | 57 (25) | 2/2 | 0 | 2 (2) | 14 (6) | 2 (3) | 46 (7) | 37 (6) |
| Val411Ile | 1 | 62 | 65 | 0/0 | 1 | 6 | 18 | 5 | 34 | 39 |
| Actin binding (+) | ||||||||||
| Arg403Gln | 20 | 33 (21) | 50 (17) | 7/2 | 4 | 3 (2) | 17 (7) | 3 (4) | 48 (9) | 45 (11) |
| Light chain binding (+) | ||||||||||
| Gly716Arg | 2 | 50 (35) | NA | 0/0 | 0 | 7 | 23 | 8 | 51 | 48 |
| Rod (0) | ||||||||||
| Leu908Val | 21 | 42 (23) | 62 (17) | 2/1 | 2 | 3 (3) | 18 (8) | 3 (3) | 39 (3) | 38 (10) |
| Rod (+) | ||||||||||
| Arg870Cys | 5 | 45 (7) | 52 (7) | 3/0 | 1 | 4 (0) | 16 | 7 | 42 | 38 |
| Glu930Lys | 2 | 35 (16) | NA | 0/0 | 1 | 3 (2) | 21 (1) | 6 (1) | 47 (1) | 49 (1) |
| Total | 74 | 41 (21) | 56 (17) | 15/5 | 10 | 3 (2) | 18 (7) | 4 (3) | 44 (6) | 42 (10) |
*Missense mutations categorised according to affected functional domain: (0), no change in overall charge of substituted amino acid at affected site; (+), change in overall charge of substituted amino acid at affected site.
†Death includes death, aborted cardiac death (resuscitated cardiac arrest or appropriate implantable cardioverter defibrillator shock), and cardiac transplantation.
Data for diagnosis, age at death, ECG Estes score, MLVWT, echo LVH score, LVEDD, and LA expressed as mean (SD).
Echo, echocardiographic; LA, left atrial diameter; LVEDD, left ventricular end diastolic diameter; MLVWT, maximum left ventricular wall thickness; NA, not applicable; NSRT, non-surgical septal reduction therapy.