Mutational Spectrum of the Succinate Semialdehyde Dehydrogenase (ALDH5A1) Gene and Functional Analysis of 27 Novel Disease-Causing Mutations in Patients with SSADH Deficiency

Shinjiro Akaboshi, Boris M. Hogema, Andrea Novelletto, Patrizia Malaspina, Gajja S. Salomons, George D. Maropoulos, Cornelis Jakobs, Markus Grompe, K. Michael Gibson

Research output: Contribution to journalArticle

80 Citations (Scopus)

Abstract

Succinate semialdehyde dehydrogenase (SSADH; ALDH5A1) deficiency, a rare metabolic disorder that disrupts the normal degradation of GABA, gives rise to a highly heterogeneous neurological phenotype ranging from mild to very severe. The nature of the mutation has so far been reported in patients from six families world wide and eight different mutations were described. Here we report the mutational spectrum in 48 additional unrelated families of different geographic origin. We detected 27 novel mutations at the cDNA level, of which 26 could be attributed to changes at the genomic level. Furthermore, six mutations were detected that did not strongly affect SSADH activity when expressed in HEK 293 cells and are considered nonpathogenic allelic variants. Twenty of the mutations were only found in one family. The spectrum of disease-causing mutations from all patients sequenced thus far consists of 25 point mutations, four small insertions, and five small deletions. Seven of these mutations affect splice junctions, seven are nonsense mutations, and 12 are missense mutations. Although there were no mutational hotspots or prevalent mutations responsible for a significant number of cases, 14 out of 37 (38%) of the missense alleles were present in exon 4 or 5. With one exception, the missense mutations we consider to be causative of SSADH deficiency reduced the SSADH activity to less than 5% of the normal activity in our in vitro expression system. This indicates that residual expression is not likely to be an important factor contributing to the large phenotypic differences observed among different families and even among siblings, suggesting that other modifying factors are of great importance in disease pathology.

Original languageEnglish (US)
Pages (from-to)442-450
Number of pages9
JournalHuman Mutation
Volume22
Issue number6
DOIs
StatePublished - 2003

Fingerprint

Succinate-Semialdehyde Dehydrogenase
Mutation
Genes
Missense Mutation
succinic semialdehyde dehydrogenase deficiency
Nonsense Codon
HEK293 Cells
Point Mutation
gamma-Aminobutyric Acid
Siblings
Exons
Complementary DNA
Alleles
Pathology
Phenotype

Keywords

  • Aldehyde dehydrogenases
  • ALDH5A1
  • GABA metabolism
  • GHB
  • SSADH
  • Succinate semialdehyde

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

Cite this

Mutational Spectrum of the Succinate Semialdehyde Dehydrogenase (ALDH5A1) Gene and Functional Analysis of 27 Novel Disease-Causing Mutations in Patients with SSADH Deficiency. / Akaboshi, Shinjiro; Hogema, Boris M.; Novelletto, Andrea; Malaspina, Patrizia; Salomons, Gajja S.; Maropoulos, George D.; Jakobs, Cornelis; Grompe, Markus; Gibson, K. Michael.

In: Human Mutation, Vol. 22, No. 6, 2003, p. 442-450.

Research output: Contribution to journalArticle

Akaboshi, Shinjiro ; Hogema, Boris M. ; Novelletto, Andrea ; Malaspina, Patrizia ; Salomons, Gajja S. ; Maropoulos, George D. ; Jakobs, Cornelis ; Grompe, Markus ; Gibson, K. Michael. / Mutational Spectrum of the Succinate Semialdehyde Dehydrogenase (ALDH5A1) Gene and Functional Analysis of 27 Novel Disease-Causing Mutations in Patients with SSADH Deficiency. In: Human Mutation. 2003 ; Vol. 22, No. 6. pp. 442-450.
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AU - Malaspina, Patrizia

AU - Salomons, Gajja S.

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