MedGen

Pseudoxanthoma elasticum (PXE) is a systemic disorder that affects the elastic tissue of the skin, the eye, and vascular system. Individuals most commonly present with angioid streaks of the retina found on routine eye examination or associated with retinal hemorrhage and/or characteristic papules in the skin. The most frequent cause of morbidity and disability in PXE is reduced vision due to complications of subretinal neovascularizations and macular atrophy. Other manifestations include premature gastrointestinal angina and/or bleeding, intermittent claudication of arm and leg muscles, stroke, renovascular hypertension, and cardiovascular complications (angina/myocardial infarction). Most affected individuals live a normal life span. [from GeneReviews]

Myofibrillar myopathy (MFM) is a noncommittal term that refers to a group of morphologically homogeneous, but genetically heterogeneous chronic neuromuscular disorders. The morphologic changes in skeletal muscle in MFM result from disintegration of the sarcomeric Z disc and the myofibrils, followed by abnormal ectopic accumulation of multiple proteins involved in the structure of the Z disc, including desmin, alpha-B-crystallin (CRYAB; 123590), dystrophin (300377), and myotilin (TTID; 604103). Genetic Heterogeneity of Myofibrillar Myopathy Other forms of MFM include MFM2 (608810), caused by mutation in the CRYAB gene (123590); MFM3 (609200), caused by mutation in the MYOT gene (604103); MFM4 (609452), caused by mutation in the ZASP gene (LDB3; 605906); MFM5 (609524), caused by mutation in the FLNC gene (102565); MFM6 (612954), caused by mutation in the BAG3 gene (603883); MFM7 (617114), caused by mutation in the KY gene (605739); MFM8 (617258), caused by mutation in the PYROXD1 gene (617220); MFM9 (603689), caused by mutation in the TTN gene (188840); MFM10 (619040), caused by mutation in the SVIL UNC45B gene (611220); MFM11 (619178), caused by mutation in the UNC45B gene (611220); MFM12 (619424), caused by mutation in the MYL2 gene (160781); and MFM13 (621078), caused by mutation in the HSPB8 gene (608014). 'Desmin-related myopathy' is another term referring to MFM in which there are intrasarcoplasmic aggregates of desmin, usually in addition to other sarcomeric proteins. Rigid spine syndrome (602771), caused by mutation in the SEPN1 gene (606210), is another desmin-related myopathy. Goebel (1995) provided a review of desmin-related myopathy. [from OMIM]

Any familial isolated dilated cardiomyopathy in which the cause of the disease is a mutation in the ACTC1 gene. [from MONDO]

Myofibrillar myopathy-6 (MFM6) is an autosomal dominant severe neuromuscular disorder characterized by onset in the first decade of progressive generalized and proximal muscle weakness, respiratory insufficiency, cardiomyopathy, and skeletal deformities related to muscle weakness. Most patients also have a motor or sensorimotor axonal peripheral neuropathy. Muscle biopsy shows fiber-type grouping, disruption of the Z lines, rimmed vacuoles, and filamentous inclusions, consistent with a myofibrillar myopathy. The disorder may cause severe disability by the second decade, leading to cardiac transplant, ventilation, and/or loss of ambulation (summary by Jaffer et al., 2012). For a phenotypic description and a discussion of genetic heterogeneity of myofibrillar myopathy (MFM), see MFM1 (601419). [from OMIM]

Any hypertrophic cardiomyopathy in which the cause of the disease is a mutation in the MYL3 gene. [from MONDO]

Restrictive cardiomyopathy (RCM) is a myocardial disease characterized by impaired ventricular filling and reduced diastolic volume in the presence of normal systolic function and normal or near-normal myocardial thickness. The disease is characterized by symptoms of progressive left- and right-sided heart failure. The overall prognosis is poor, especially when onset is in childhood, and patients often require cardiac transplantation (Mogensen et al., 2003). Genetic Heterogeneity of Familial Restrictive Cardiomyopathy Other forms of familial restrictive cardiomyopathy include RCM2 (609578), mapped to chromosome 10q23; RCM3 (612422), caused by mutation in the TNNT2 gene (191045) on chromosome 1q32; RCM4 (see 615248), caused by mutation in the MYPN gene (608517) on chromosome 10q21; RCM5 (see 617047), caused by mutation in the FLNC gene (102565) on chromosome 7q32; and RCM6 (619433), caused by mutation in the KIF20A gene (605664) on chromosome 5q31. [from OMIM]

Familial restrictive cardiomyopathy is a genetic form of heart disease. For the heart to beat normally, the heart (cardiac) muscle must contract and relax in a coordinated way. Oxygen-rich blood from the lungs travels first through the upper chambers of the heart (the atria), and then to the lower chambers of the heart (the ventricles).

In people with familial restrictive cardiomyopathy, the heart muscle is stiff and cannot fully relax after each contraction. Impaired muscle relaxation causes blood to back up in the atria and lungs, which reduces the amount of blood in the ventricles.

Familial restrictive cardiomyopathy can appear anytime from childhood to adulthood. The first signs and symptoms of this condition in children are failure to gain weight and grow at the expected rate (failure to thrive), extreme tiredness (fatigue), and fainting. Children who are severely affected may also have abnormal swelling or puffiness (edema), increased blood pressure, an enlarged liver, an abnormal buildup of fluid in the abdominal cavity (ascites), and lung congestion. Some children with familial restrictive cardiomyopathy do not have any obvious signs or symptoms, but they may die suddenly due to heart failure. Without treatment, the majority of affected children survive only a few years after they are diagnosed.

Adults with familial restrictive cardiomyopathy typically first develop shortness of breath, fatigue, and a reduced ability to exercise. Some individuals have an irregular heart beat (arrhythmia) and may also experience a sensation of fluttering or pounding in the chest (palpitations) and dizziness. Abnormal blood clots are commonly seen in adults with this condition. Without treatment, approximately one-third of adults with familial restrictive cardiomyopathy do not survive more than five years after diagnosis. [from MedlinePlus Genetics]

Multiple congenital anomalies-hypotonia-seizures syndrome is an autosomal recessive disorder characterized by neonatal hypotonia, lack of psychomotor development, seizures, dysmorphic features, and variable congenital anomalies involving the cardiac, urinary, and gastrointestinal systems. Most affected individuals die before 3 years of age (summary by Maydan et al., 2011). The disorder is caused by a defect in glycosylphosphatidylinositol (GPI) biosynthesis. For a discussion of genetic heterogeneity of MCAHS, see MCAHS1 (614080). For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293). [from OMIM]

Idiopathic hypereosinophilic syndrome (HES) is a myeloproliferative disorder in which persistent eosinophilia leads to tissue damage, caused by direct infiltration by eosinophils and cytokine release, which leads to progressive organ dysfunction that may be fatal (summary by Griffin et al., 2003). [from OMIM]

Any autosomal recessive primary microcephaly in which the cause of the disease is a mutation in the CENPE gene. [from MONDO]

Infantile-onset myofibrillar myopathy-12 with cardiomyopathy (MFM12) is a severe autosomal recessive disorder affecting both skeletal and cardiac muscle tissue that is apparent in the first weeks of life. Affected infants show tremor or clonus at birth, followed by onset of rapidly progressive generalized muscle weakness and dilated cardiomyopathy and cardiac failure, usually resulting in death by 6 months of age. Skeletal and cardiac muscle tissues show hypotrophy of type I muscle fibers and evidence of myofibrillar disorganization (summary by Weterman et al., 2013). For a discussion of genetic heterogeneity of myofibrillar myopathy, see MFM1 (601419). [from OMIM]

Immunodeficiency-80 with or without congenital cardiomyopathy (IMD80) is an autosomal recessive immunologic disorder with variable manifestations. One patient with infantile-onset of chronic cytomegalovirus (CMV) infection associated with severely decreased NK cells has been reported. Another family with 3 affected fetuses showing restrictive cardiomyopathy and hypoplasia of the spleen and thymus has also been reported (summary by Baxley et al., 2021). [from OMIM]

Familial restrictive cardiomyopathy-6 (RCM6) is characterized by prenatal onset of severe restrictive cardiomyopathy predominantly involving the right ventricle, resulting in irreversible heart failure and early death (Louw et al., 2018). For a general phenotypic description and discussion of genetic heterogeneity of familial restrictive cardiomyopathy, see RCM1 (115210). [from OMIM]

Restrictive left ventricular physiology is characterized by a pattern of ventricular filling in which increased stiffness of the myocardium causes ventricular pressure to rise precipitously with only small increases in volume, defined as restrictive ventricular physiology in the presence of normal or reduced diastolic volumes (of one or both ventricles), normal or reduced systolic volumes, and normal ventricular wall thickness. [from HPO]