Cardiac arrhythmias - additional genes

Gene: MLIP

Red List (low evidence)

Comment on classification of this gene: The rating for this gene should be added as RED, as the implication of this gene in cardiac arrhythmias was identified from biallelic variants from only one family (despite a mild ventricular dysfunction in another unrelated individual). However, this is well supported by results from functional studies from human tissue samples and mouse models.

Five individuals from two different pedigrees carrying two different novel homozygous nonsense variants were reported with myopathy characterized by hyperCKemia and with absence of rhabdomyolysis. The age of onset of symptoms for the single patient from family 1 is 2.5 years. All four individuals (age ranges from 24 to 37) from family 2 (Amish ancestry) were reported either with Sinus arrhythmia or Sinus bradycardia and one of these individuals displayed left ventricular hypertrophy. It was also found that there is founder effect for this allele in the Amish population in the resident county of these individuals (PMID:34935254).

Seven patients from six families carrying six different biallelic (either homozygous or compound heterozygous) variants in MLIP gene were presented with a consistent phenotype including mild muscle weakness, exercise-induced muscle pain, variable susceptibility to episodes of rhabdomyolysis, and persistent basal elevated serum creatine kinase (CK) levels. The age of onset of symptoms ranged from 8 months to 7 years. However, mild left ventricular dysfunction was reported only in one patient, despite the presence of mild structural abnormalities in two other patients (PMID:34581780).

The expression of MLIP was identified to be reduced in patients with dilated cardiomyopathy, as studied from LV samples from patients with terminal-stage heart failure. In addition, deletion of MLIP gene accelerated progress from hypertrophy to heart failure in several cardiomyopathy models and overexpression prevented pathologic remodelling and preserved cardiac function (PMID:26436652). MLIP has also been identified as a regulator of myoblast differentiation (PMID:33802236) and myonuclear positioning (PMID:32719146).
Sources: Literature

Created: 11 Dec 2022, 9:37 p.m.

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Myopathy with myalgia, increased serum creatine kinase, and with or without episodic rhabdomyolysis, MIM# 620138; Arrhythmia, HP:0011675

Publications

• 26436652
• 32719146
• 33802236
• 34581780
• 34935254