Biology ·
15 Common Enzyme Deficiency Diseases
15 Common Enzyme Deficiency Diseases
| Disease | Missing Enzyme | Symptoms | Genetics | Diagnostic Test | Prognosis |
|---|---|---|---|---|---|
| Pompe disease (Glycogen storage disease II) | Acid alpha-glucosidase (GAA) | Muscle weakness, hypotonia, cardiomyopathy (infantile), respiratory insufficiency (late-onset) | Autosomal recessive | Blood/plasma GAA activity, genetic testing, muscle biopsy | Infantile: poor without treatment; Late-onset: progressive, improved with enzyme replacement |
| Tay-Sachs disease | Hexosaminidase A (HEXA) | Neurodegeneration, developmental delay, cherry-red spot on retina, seizures | Autosomal recessive | Enzyme assay (Hex A activity), genetic testing | Fatal by 3–5 years (infantile form) |
| Gaucher disease | Glucocerebrosidase (GBA) | Hepatosplenomegaly, anemia, thrombocytopenia, bone pain | Autosomal recessive | Enzyme assay, genetic testing | Variable; type 1 treatable with ERT, type 2 severe neurologic involvement |
| Phenylketonuria (PKU) | Phenylalanine hydroxylase (PAH) | Intellectual disability, seizures, fair skin, musty odor | Autosomal recessive | Blood phenylalanine levels, PAH gene testing | With diet: normal development; untreated: severe cognitive impairment |
| Maple Syrup Urine Disease (MSUD) | Branched-chain alpha-keto acid dehydrogenase complex | Sweet-smelling urine, poor feeding, vomiting, neurologic deficits | Autosomal recessive | Plasma amino acid analysis, enzyme assay, genetic testing | Early treatment: normal development; untreated: life-threatening |
| Albinism (Oculocutaneous Type I) | Tyrosinase | Hypopigmentation of skin, hair, eyes; vision problems | Autosomal recessive | Genetic testing, enzyme activity in cultured melanocytes | Normal life expectancy; risk of skin cancer, visual impairment |
| Krabbe disease | Galactocerebrosidase (GALC) | Neurodegeneration, irritability, hypotonia, seizures | Autosomal recessive | Enzyme assay, genetic testing, MRI | Infantile: fatal within 2 years; later-onset: variable progression |
| Fabry disease | Alpha-galactosidase A | Pain (acroparesthesia), angiokeratomas, kidney and heart involvement | X-linked recessive | Enzyme activity, genetic testing | Progressive organ damage; ERT improves outcomes |
| Hunter syndrome (MPS II) | Iduronate-2-sulfatase | Coarse facial features, developmental delay, joint stiffness, organomegaly | X-linked recessive | Enzyme assay, urinary glycosaminoglycans, genetic testing | Severe forms: early death; attenuated: survival to adulthood with therapy |
| Hurler syndrome (MPS I) | Alpha-L-iduronidase | Developmental delay, coarse facial features, hepatosplenomegaly, corneal clouding | Autosomal recessive | Enzyme assay, urinary glycosaminoglycans, genetic testing | Severe forms fatal by early teens; mild forms may survive into adulthood |
| Niemann-Pick disease (Type A/B) | Acid sphingomyelinase | Neurodegeneration, hepatosplenomegaly, failure to thrive | Autosomal recessive | Enzyme assay, genetic testing | Type A: fatal in early childhood; Type B: variable, survives into adulthood |
| Ornithine transcarbamylase deficiency (OTC deficiency) | Ornithine transcarbamylase | Hyperammonemia, vomiting, lethargy, encephalopathy | X-linked recessive | Plasma ammonia, urine orotic acid, genetic testing | Severe neonatal forms can be fatal; late-onset: variable |
| Mucopolysaccharidosis VI (Maroteaux-Lamy) | Arylsulfatase B | Skeletal abnormalities, coarse facial features, organomegaly | Autosomal recessive | Enzyme assay, urinary GAGs, genetic testing | Progressive; enzyme replacement therapy improves outcomes |
| Galactosemia | Galactose-1-phosphate uridyltransferase (GALT) | Feeding difficulties, jaundice, liver failure, cataracts | Autosomal recessive | Blood galactose, enzyme assay, genetic testing | With diet: good prognosis; untreated: life-threatening |
| Leucine-rich alpha-2-glycoprotein deficiency (LSD) | Lysosomal acid lipase (LAL) | Hepatosplenomegaly, dyslipidemia, liver fibrosis | Autosomal recessive | Enzyme assay, genetic testing | Early-onset: poor prognosis; late-onset treatable with ERT |
