Browsing Pathways

beta-Ketothiolase Deficiency (2-Methyl-3-Hydroxybutyric Acidemia; Mitochondrial Acetoacetyl-CoA Thiolase Deficiency; MAT Deficiency; T2 Deficiency; 3-KTD Deficiency; 3-Ketothiolase Deficiency) is an autosomal recessive disease caused by a mutation in the HADHB gene which codes for beta-ketathiolase. A deficiency in this enzyme results in accumulation of ammonia and ketone bodies in blood; and 2-methyl-3-hydroxybutyric acid, 2-methylacetoacetic acid, 3-hydroxybutyric acid, tiglylglycine, and ketone bodies in urine. Symptoms include ketosis, seizures, organic acids in urine, and hyperammonemia. Treatment includes a low protein diet and L-carnitine.h3. h2.

Beta-ureidopropionase deficiency (Beta Alanine-Synthase Deficiency, UPB1, BUP1) is an autosomal recessive disease caused by mutations in the UPB1 gene which codes for beta-ureidopropionase. A deficiency in this enzyme results in accumulation of N-carbamyl-beta-amino acids. Symptoms include hypotonia, dystonic movements, scoliosis, microcephaly, and severe developmental delay.

Aspartylglucosaminuria is an autosomal recessive disorder of lysosomal storage caused by a mutation in the AGA gene which codes for N(4)-(beta-N-acetylglucosaminyl)-L-asparaginase. A deficiency in this enzyme results in accumulation of aspartylglycosamine and oligosaccharides in urine. Symptoms, which present in childhood, include skeletal changes, speech abnormalities, macroglossia, and mental retardation. Treatment includes bone marrow transplants.

Aromatic L-Aminoacid Decarboxylase Deficiency (DOPA decarboxylase; DDC) is an autosomal recessive disease caused by a mutation in the DDC gene which codes for aromatic-L-aminoacid decarboxylase. A deficiency in this enzyme results in accumulation of 3-methoxytyrosine, 5-hydroxy-L-tryptophan, and L-Dopa in plasma, spinal fluid, and urine; 3-methoxytyramine and dopamine in urine. It also results in decreased concentrations of homovanillic acid, S-adenosylmethionine, and 5-hydroxytryptophol in spinal fluid; and epinephrine, norepinephrine in plasma. Symptoms include temperature instability, hypotonia, mental and motor retardation, and cerebral atrophy.

Alkaptonuria (Homogentisic acid oxidase deficiency) is an autosomal recessive disease caused by a mutation in the HGD gene which codes for homogentisate 1,2-dioxygenase. A mutation in this enzyme results in accumulation of homogentisic acid in urine. Symptoms, which present in adulthood, include arthritis, black or brown urine, and urolithiasis. Treatment includes a low-protein diet with vitamin C.

AICA-ribosiduria is a metabolic disease caused by a defect in final steps of purine de novo biosynthesis. This defect is caused by a mutation in the ATIC which codes for bifunctional purine biosynthesis protein PURH. A deficiency in this enzyme results in accumulation of 5-aminoimidazole-4-carboxamide in urine. Symptoms include mental retardation, epilepsy, dysmorphic features, and congenital blindness.

Adenylosuccinate Lyase Deficiency. (Adenylosuccinase Deficiency ; Adenylosuccinate monophosphate lyase deficiency) is a rare autosomal recessive disease caused by a mutation in the ADSL gene which codes for adenylosuccinate lyase. A deficiency in this enzyme results in accumulation of succinyladenosine in plasma, spinal fluid, and urine. Symptoms, which present at birth, include hyptonia, seizures, mental retardation, and encephalopathy. Treatment includes allopurinol.

Adenosine deaminiase deficiency (immunodeficiency) is an autosomal recessive disease caused by a muation in the ADA gene which codes for adenosine deaminase. A deficiency in this enzyme results in immunodeficiency and a decreased concentration of lymphocytes in blood. Symptoms include diarrhea, severe or recurrent infections, vomiting and early onset in children, infants and newborns. Treatment includes bone-marrow transplants and enzyme replacement therapy.

5-Oxoprolinuria (5-Oxoprolinase deficiency) is a result of a defect in the gamma-glutamyl cycle due to either 5-oxoprolinase or glutathione synthetase deficiency. In the case of glutathione synthetase deficiency, the glycine is not incorporated into gamma-glutamylcysteine. In the case of 5-oxoprolinase, however, pyroglutamic acid accumulates. Symptoms include anemia, mental retardation, metabolic acidosis, respiratory distress and urolithiasis.

3-Methylglutaconic Aciduria Type IV, also called MGA, Type IV and MGA4, is a rare inborn error of metabolism (IEM) and autosomal recessive disorder and caused by a defective methylglutaconyl-CoA hydratase. Methylglutaconyl-CoA hydratase catalyzes the conversion of 3-Methylglutaconyl-CoA into 3-Hydroxy-3-methylglutaryl-CoA which is the substrate of hydroxymethylglutaryl-CoA lyase. This disorder is characterized by increased urinary excretion of 3-methylglutaconic acid. Symptoms of the disorder include poor growth and neurological degression. Currently, there is no effective treatment for 3-MGA type IV.