TABLE 4.

Typical features of common types of syndromic hypertrophic cardiomyopathy (phenocopies).

Disease	Common pathogenic gene variants and protein product	Patterns of inheritance	Clinical features
Anderson-Fabry disease	GLA – α-galactosidase A	XL	Peripheral neuralgia and autonomic dysfunction. Ischemic strokes and arrhythmias. Angiokeratomas, hearing loss. Microalbuminuria and kidney failure. Female carriers are variably affected. The presentation starts during adolescence.
Danon disease	LAMP2 – lysosome-associated membrane protein 2	XL	Skeletal myopathy in proximal muscle groups. Increased serum creatine kinase. Arrhythmias. Female carriers are variably affected.
Friedreich’s ataxia	FRDA – Frataxin	AR	Progressive ataxia of the limbs. Progressive skeletal muscle weakness. Onset varies throughout adulthood.
Kearns–Sayre syndrome	Mitochondrial DNA	Mitochondrial	Pigmentary retinopathy. Progressive external ophthalmoplegia. Onset before 20 years. cardiac conduction defects. Increased CSF protein concentration. Cerebellar ataxia.
Noonan syndrome	PTPN11 (50% of Noonan cases) – tyrosine phosphatase SHP-2	AD	Prominent forehead, eyes, webbing of neck. Pulmonary valve stenosis, atrial septal defect. Platelet dysfunction and coagulation factors deficiency. Peripheral lymphedema. Pectus excavatum and growth retardation.
Pompe disease	GAA – acid alpha-glucosidase	AR	Progressive weakness of proximal muscles Macroglossia, hepatomegaly, feeding and respiratory difficulties, hearing loss. Arrhythmias. Onset varies from birth (classic infantile) through adulthood.

AD, autosomal dominant; AR, autosomal recessive; XL, X-linked; CSF, cerebrospinal fluid.