Genetics of laminopathy
Laminopathies are due to genetic mutations in the lamin A/C gene (LMNA). Genetic mutations occur in our DNA when the DNA sequence is changed. The change, or mistake, in the DNA can affect how the Lamin protein is made. All persons make Lamin protein in their cells. The precise functions of Lamin proteins are still being researched although it is generally accepted that Lamin proteins help provide mechanical support for the cell nucleus and may control the activities of some genes. In persons with a Laminopathy, the Lamin protein is made abnormally due to the DNA mutation. Sometimes this abnormality means that the diseased Lamin protein has a different length or shape; in other cases the amount of the Lamin protein maybe abnormal. More information about genetic disorders in general can be found at the National Human Genome Research Institute.
For some persons, the LMNA mutation may be inherited from a parent or it can be brand-new mutation, often referred to as a 'spontaneous mutation'. The genetic nature of Laminopathies means that it is important for many persons with LMNA mutations to understand the risks to other persons in their family, including future children.
The inheritance pattern in dilated cardiomyopathy due to LMNA mutations is an autosomal dominant pattern. Briefly, this means that an individual with a LMNA mutation has a 50% risk of passing that mutation onto each of his or her children. Autosomal dominant inheritance also implies that both males and females are equally at risk to inherit a LMNA mutation from a parent who has a LMNA mutation.
Diagnosis of Laminopathies:
In most cases, a diagnosis of a LMNA mutation will require genetic testing. Genetic testing is usually performed from a blood sample. As genetic testing can be complicated the results are best interpreted by a knowledgeable physician, genetic counselor, or other health care provider.