Aminoacylase 1 deficiency

Aminoacylase 1 deficiency is a rare inborn error of metabolism. To date only 21 cases have been described.^[1]^[2]

History

This disorder was first reported in 2005.^[3]

Molecular biology

Aminoacylase 1 (ACY1: EC 3.5.14) is a zinc binding enzyme which hydrolyzes N-acetyl amino acids into the free amino acid and acetic acid. Of the N-actyl amino hydrolyzing enzymes, aminoacylase 1 is the most common.

The ACY1 gene is located on the short arm of chromosome 3 (3p21.2).

Genetics

This disorder in inherited in an autosomal recessive fashion.

Signs and symptoms

The clinical picture is heterogeneous and includes motor delay, seizures, moderate to severe mental retardation, absent speech, growth delay, muscular hypotonia and autistic features.

Diagnosis

There is a specific pattern of N-acetyl amino acid excretion in the urine. The diagnosis can be confirmed by sequencing of the aminoacylase 1 gene.

References

↑ Ferri L, Funghini S, Fioravanti A, Biondi E, La Marca G, Guerrini R, Donati M, Morrone A (2013) Aminoacylase I deficiency due to ACY1 mRNA exon skipping. Clin Genet doi: 10.1111/cge.12297
↑ Sass JO, Mohr V, Olbrich H, Engelke U, Horvath J, Fliegauf M, Loges NT, Schweitzer-Krantz S, Moebus R, Weiler P, Kispert A, Superti-Furga A, Wevers RA, Omran H (2006) Mutations in ACY1, the gene encoding aminoacylase 1, cause a novel inborn error of metabolism. Am J Hum Genet 78(3):401-409
↑ Van Coster RN, Gerlo EA, Giardina TG, Engelke UF, Smet JE, De Praeter CM, Meersschaut VA, De Meirleir LJ, Seneca SH, Devreese B, Leroy JG, Herga S, Perrier JP, Wevers RA, Lissens W (2005) Aminoacylase I deficiency: a novel inborn error of metabolism. Biochem Biophys Res Commun 338(3):1322-1326

Inborn error of amino acid metabolism (E70–E72, 270)

K→acetyl-CoA

Lysine/straight chain	Glutaric acidemia type 1 type 2 Hyperlysinemia Pipecolic acidemia Saccharopinuria

Leucine	3-hydroxy-3-methylglutaryl-CoA lyase deficiency 3-Methylcrotonyl-CoA carboxylase deficiency 3-Methylglutaconic aciduria 1 Isovaleric acidemia Maple syrup urine disease

Tryptophan	Hypertryptophanemia

G→pyruvate→citrate

Glycine	D-Glyceric acidemia Glutathione synthetase deficiency Sarcosinemia Glycine→Creatine: GAMT deficiency Glycine encephalopathy

G→glutamate→
α-ketoglutarate

Histidine	Carnosinemia Histidinemia Urocanic aciduria

Proline	Hyperprolinemia Prolidase deficiency

Glutamate/glutamine	SSADHD

G→propionyl-CoA→
succinyl-CoA

Valine	Hypervalinemia Isobutyryl-CoA dehydrogenase deficiency Maple syrup urine disease

Isoleucine	2-Methylbutyryl-CoA dehydrogenase deficiency Beta-ketothiolase deficiency Maple syrup urine disease

Methionine	Cystathioninuria Homocystinuria Hypermethioninemia

General BC/OA	Methylmalonic acidemia Methylmalonyl-CoA mutase deficiency Propionic acidemia

G→fumarate

Phenylalanine/tyrosine

Phenylketonuria	6-Pyruvoyltetrahydropterin synthase deficiency Tetrahydrobiopterin deficiency

Tyrosinemia	Alkaptonuria/Ochronosis Type I tyrosinemia Type II tyrosinemia Type III tyrosinemia/Hawkinsinuria

Tyrosine→Melanin	Albinism: Ocular albinism (1) Oculocutaneous albinism (Hermansky–Pudlak syndrome) Waardenburg syndrome

Tyrosine→Norepinephrine	Dopamine beta hydroxylase deficiency reverse: Brunner syndrome

G→oxaloacetate

Urea cycle/Hyperammonemia (arginine aspartate)	Argininemia Argininosuccinic aciduria Carbamoyl phosphate synthetase I deficiency Citrullinemia N-Acetylglutamate synthase deficiency Ornithine transcarbamylase deficiency/translocase deficiency

Transport/
IE of RTT

Other

Index of inborn errors of metabolism

Description	Metabolism Enzymes and pathways: citric acid cycle enzymes pentose phosphate intermediates glycoproteins enzymes glycosaminoglycans proteoglycan enzymes phospholipid metabolism cholesterol and steroid intermediates sphingolipids enzymes eicosanoids enzymes amino acid intermediates urea cycle enzymes nucleotide intermediates

Disorders	Citric acid cycle and electron transport chain Glycoprotein Proteoglycan Fatty-acid Phospholipid Cholesterol and steroid Eicosanoid Amino acid Purine-pyrimidine Heme metabolism Symptoms and signs

Treatment	Drugs other