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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed June 2007

What is the official name of the ALDH4A1 gene?

The official name of this gene is “aldehyde dehydrogenase 4 family member A1.”

ALDH4A1 is the gene's official symbol. The ALDH4A1 gene is also known by other names, listed below.

What is the normal function of the ALDH4A1 gene?

The ALDH4A1 gene provides instructions for producing the enzyme pyrroline-5-carboxylate dehydrogenase, which is found in tissues throughout the body. Within the cells of these tissues, this enzyme functions in energy-producing structures called mitochondria.

Pyrroline-5-carboxylate dehydrogenase starts the second step in the process that breaks down the protein building block (amino acid) proline. This step converts pyrroline-5-carboxylate, which is produced in the first step, to the amino acid glutamate. The conversion between proline and glutamate is important in maintaining a supply of the amino acids needed for protein production, and for energy transfer within the cell.

Does the ALDH4A1 gene share characteristics with other genes?

The ALDH4A1 gene belongs to a family of genes called ALDH (aldehyde dehydrogenases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the ALDH4A1 gene related to health conditions?

hyperprolinemia - caused by mutations in the ALDH4A1 gene

Researchers have identified three mutations in the ALDH4A1 gene that eliminate the function of the pyrroline-5-carboxylate dehydrogenase enzyme, causing hyperprolinemia type II. Two of these mutations add or delete a DNA building block (nucleotide), which introduces a premature stop signal that results in an abnormally shortened enzyme. The third mutation results in the substitution of the amino acid leucine for the amino acid serine at position 352 (written as Ser352Leu or S352L) in the pyrroline-5-carboxylate dehydrogenase enzyme. Nonfunctional pyrroline-5-carboxylate dehydrogenase leads to elevated levels of proline and a buildup of the intermediate breakdown product pyrroline-5-carboxylate, causing the signs and symptoms of hyperprolinemia type II.

Where is the ALDH4A1 gene located?

Cytogenetic Location: 1p36

Molecular Location on chromosome 1: base pairs 18,871,430 to 18,902,799

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The ALDH4A1 gene is located on the short (p) arm of chromosome 1 at position 36.

The ALDH4A1 gene is located on the short (p) arm of chromosome 1 at position 36.

More precisely, the ALDH4A1 gene is located from base pair 18,871,430 to base pair 18,902,799 on chromosome 1.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about ALDH4A1?

You and your healthcare professional may find the following resources about ALDH4A1 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the ALDH4A1 gene or gene products?

  • aldehyde dehydrogenase 4A1
  • aldehyde dehydrogenase 4 family, member A1
  • ALDH4
  • mitochondrial delta-1-pyrroline 5-carboxylate dehydrogenase
  • P5CD
  • P5C dehydrogenase
  • P5CDh
  • P5CDhL
  • P5CDhS

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding ALDH4A1?

acids ; aldehyde ; amino acid ; breakdown ; carboxylate ; cell ; dehydrogenase ; DNA ; enzyme ; gene ; leucine ; mitochondria ; mutation ; nucleotide ; proline ; protein ; serine ; substitution

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Geraghty MT, Vaughn D, Nicholson AJ, Lin WW, Jimenez-Sanchez G, Obie C, Flynn MP, Valle D, Hu CA. Mutations in the Delta1-pyrroline 5-carboxylate dehydrogenase gene cause type II hyperprolinemia. Hum Mol Genet. 1998 Sep;7(9):1411-5. (
  • Hu CA, Lin WW, Valle D. Cloning, characterization, and expression of cDNAs encoding human delta 1-pyrroline-5-carboxylate dehydrogenase. J Biol Chem. 1996 Apr 19;271(16):9795-800. (
  • Inagaki E, Ohshima N, Takahashi H, Kuroishi C, Yokoyama S, Tahirov TH. Crystal structure of Thermus thermophilus Delta1-pyrroline-5-carboxylate dehydrogenase. J Mol Biol. 2006 Sep 22;362(3):490-501. Epub 2006 Jul 29. (
  • NCBI Gene (
  • Sophos NA, Vasiliou V. Aldehyde dehydrogenase gene superfamily: the 2002 update. Chem Biol Interact. 2003 Feb 1;143-144:5-22. (
  • Vasiliou V, Bairoch A, Tipton KF, Nebert DW. Eukaryotic aldehyde dehydrogenase (ALDH) genes: human polymorphisms, and recommended nomenclature based on divergent evolution and chromosomal mapping. Pharmacogenetics. 1999 Aug;9(4):421-34. Review. (
  • Vasiliou V, Pappa A. Polymorphisms of human aldehyde dehydrogenases. Consequences for drug metabolism and disease. Pharmacology. 2000 Sep;61(3):192-8. Review. (
  • Yoshida A, Rzhetsky A, Hsu LC, Chang C. Human aldehyde dehydrogenase gene family. Eur J Biochem. 1998 Feb 1;251(3):549-57. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: June 2007
Published: February 8, 2016