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FB2026_01
,
released March 12, 2026
This report describes dilated cardiomyopathy 1S (CMD1S), which is a subtype of dilated cardiomyopathy; CMD1S exhibits an autosomal dominant pattern of inheritance. CMD1S is one of several forms of heart disease associated with the human myosin heavy chain gene MYH7. In flies there is one gene, Mhc, orthologous to the ten genes in humans that encode forms of muscle myosin class II heavy chain; MYH7 and MYH6 are reciprocal bests hits of Dmel\Mhc. Additional information about fly models for this and related diseases can be found in the report 'cardiomyopathy, MYH6-MYH7-related' (FBhh0000422).
The human MYH7 gene has not been introduced into flies.
A UAS construct of Dmel\Mhc with a mutant analogous to a variant implicated in CMD1S (S532P in human MYH7, S531P in the fly gene) has been characterized. Assessed in animals homozygous for a mutation of Dmel\Mhc that specifically eliminates Mhc protein expression in indirect flight muscles and jump muscles, adults carrying the variant form exhibit muscle fiber functional deficits and a progressive decline in locomotion. Using animals heterozygous for a null mutation of Dmel\Mhc and one or two copies of the transgene with the S532P/S531P variant, a dose-dependent phenotype of cardiac dilation is observed in young adults; adult lifespan is reduced.
[updated Oct. 2021 by FlyBase; FBrf0222196]
Nonsyndromic isolated dilated cardiomyopathy (DCM) is characterized by left ventricular enlargement and systolic dysfunction, a reduction in the myocardial force of contraction. DCM usually presents with any one of the following: (1) Heart failure with symptoms of congestion (edema, orthopnea, paroxysmal nocturnal dyspnea) and/or reduced cardiac output (fatigue, dyspnea on exertion); (2) arrhythmias and/or conduction system disease; (3) thromboembolic disease (from left ventricular mural thrombus) including stroke. [from Dilated Cardiomyopathy Overview, pubmed:20301486 2016.01.26]
Dilated cardiomyopathy (CMD) is characterized by cardiac dilatation and reduced systolic function. CMD is the most frequent form of cardiomyopathy and accounts for more than half of all cardiac transplantations performed in patients between 1 and 10 years of age. A heritable pattern is present in 20 to 30% of cases. Most familial CMD pedigrees show an autosomal dominant pattern of inheritance, usually presenting in the second or third decade of life (summary by Levitas et al., 2010, pubmed:20551992). [from MIM:115200, 2016.01.27]
[CARDIOMYOPATHY, DILATED, 1S; CMD1S](https://omim.org/entry/613426)
[MYOSIN, HEAVY CHAIN 7, CARDIAC MUSCLE, BETA; MYH7](https://omim.org/entry/160760)
Kamisago et al. (2000, pubmed:11106718) studied affected members of a large 4-generation family segregating autosomal dominant dilated cardiomyopathy (CMD). Seventeen family members had dilated cardiomyopathy without conduction system disease, skeletal muscle dysfunction, or other phenotypes. The authors noted that previous clinical studies of 12 affected individuals showed no evidence of ventricular hypertrophy. In many family members, the onset of disease occurred early in life: one patient was hospitalized with heart failure at 2 years of age; another developed heart failure followed by sudden death at 20 years of age; and another underwent cardiac transplantation for end-stage heart failure at 23 years of age. Histopathologic study of the explanted heart from the last patient showed mildly increased interstitial fibrosis without myocyte or myofibrillar disarray. [From MIM:613426, 2016.02.01]
Dilated cardiomyopathy-1S (CMD1S) is caused by heterozygous mutation in the MYH7 gene. Mutation in the MYH7 gene has also been associated with left ventricular noncompaction (LVNC5; MIM:613426), hypertrophic cardiomyopathy (CMH1; MIM:192600), and myosin storage myopathy (MIM:608358). [From MIM:613426, 2016.02.01]
Muscle myosin is a hexameric protein containing 2 heavy chain subunits, 2 alkali light chain subunits, and 2 regulatory light chain subunits. This gene encodes the beta (or slow) heavy chain subunit of cardiac myosin. It is expressed predominantly in normal human ventricle. It is also expressed in skeletal muscle tissues rich in slow-twitch type I muscle fibers. Changes in the relative abundance of this protein and the alpha (or fast) heavy subunit of cardiac myosin correlate with the contractile velocity of cardiac muscle. Its expression is also altered during thyroid hormone depletion and hemodynamic overloading. [provided by RefSeq, Jul 2008]
Many to one: 10 human to 1 Drosophila.