Novel ALDH3A2 mutations in structural and functional domains of FALDH causing diverse clinical phenotypes in Sjögren–Larsson syndrome patients (original) (raw)
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Sj�gren-Larsson syndrome: Seven novel mutations in the fatty aldehyde dehydrogenase gene ALDH3A2
Human Mutation, 2004
Sjögren-Larsson syndrome (SLS) is an inherited neurocutaneous disease caused by mutations in the ALDH3A2 gene that codes for fatty aldehyde dehydrogenase (FALDH), an enzyme involved in lipid metabolism. We performed mutation analysis in probands or fetuses from 13 unrelated SLS families and identified seven novel ALDH3A2 mutations. Two mutations involved an insertion or deletion of a single guanine nucleotide at the same position in exon 9: c.1223delG and c.1223_1224insG. A 66-bp duplication in exon 2 probably arose from unequal crossing over within a mispaired 10-bp sequence that is normally repeated within the exon. Based on RT-PCR of fibroblast RNA, the c.1107+2T>G donor splice-site mutation in intron 7 produced two mRNA transcripts, one skipping exon 7 and the other skipping exons 6-8. Expression of the c.1139G>A mutation in exon 8, which is predicted to cause an amino acid substitution (Ser380Asn) in an evolutionarily conserved region of the FALDH catalytic domain, resulted in a protein with profoundly reduced enzymatic activity. By analyzing single nucleotide polymorphisms within the ALDH3A2 gene, we detected four different haplotypes among the new mutant alleles. These results demonstrate a rich diversity of mutations and haplotype associations in SLS.
Molecular Genetics and Metabolism, 2007
Sjögren-Larsson syndrome (SLS) is an inherited neurocutaneous disorder caused by mutations in the ALDH3A2 gene that encodes fatty aldehyde dehydrogenase (FALDH), an enzyme that catalyzes the oxidation of fatty aldehyde to fatty acid. Affected patients display ichthyosis, mental retardation and spastic diplegia. More than 70 mutations in ALDH3A2 have been discovered in SLS patients including amino acid substitutions, deletions, insertions and splicing errors. Most mutations are private, but several common mutations reflect founder effects, consanguinity or recurrent mutational events. FALDH oxidizes fatty aldehyde substrates arising from metabolism of fatty alcohols, leukotriene B4, ether glycerolipids and other potential sources such as sphingolipids. The pathogenesis of the cutaneous and neurologic symptoms is thought to result from abnormal lipid accumulation in the membranes of skin and brain; the formation of aldehyde Schiff base adducts with amine-containing lipids or proteins; or defective eicosanoid metabolism. Therapeutic approaches are being developed to target specific metabolic defects associated with FALDH deficiency or to correct the genetic defect by gene transfer.
Sjögren–Larsson syndrome: Novel mutations in the ALDH3A2 gene in a French cohort
Journal of The Neurological Sciences
Sjogren-Larsson syndrome (SLS) is a rare autosomal recessive disorder characterized by ichthyosis, spastic dior tetraplegia and mental retardation due a defect of the fatty aldehyde dehydrogenase (FALDH), related to mutations in the ALDH3A2 gene. In this study, we screened a French cohort of patients with Sjögren-Larsson syndrome (SLS) for mutations in the ALDH3A2 gene. The five unrelated patients with typical SLS all present mutations in this gene. Three novel mutations were identified whereas three other ones were previously described. We also realized functional analyses at the mRNA level for two splice site mutations to study their deleterious consequences. Two of the previously described mutations had already been identified in the same region of Europe, suggesting a putative founder effect. We suggest that, (1) when clinical and MR features are present, direct sequencing of the ALDH3A2 gene in SLS is of particular interest without necessity of a skin biopsy for enzymatic assay in order to propose genetic counsel and (2) identification of mutations already described in the same population with putative founder effects may simplify genetic analysis in this context.
Assessment of ten Egyptian patients with Sjögren-Larsson syndrome (SLS) detected; unusual clinical manifestations, a first report of brain atrophy in SLS, some patients exhibited neither retinal dots nor white matter changes previously reported as essential manifestations. We identified five mutations in ALDH3A2 gene including a novel one and suggest a founder effect. Sjögren-Larsson syndrome is a rare autosomal recessive inborn error of lipid metabolism caused by mutations in the ALDH3A2 gene that codes for fatty aldehyde dehydrogenase and result in a triad of ichthyosis, spasticity, and mental retardation. Clinical, radiological, biochemical, and neurophysiological evaluation in ten SLS patients descending from seven unrelated Egyptian pedigrees was followed by Sanger sequencing of ALDH3A2 performed by ABI 3500. All patients presented with SLS triad; ichthyosis, spasticity of four limbs and hyperreflexia with an intelligent quotient (IQ) ranging from (39 to 69). Other manifestations were dysmorphic features, seizures, and skeletal and ophthalmological affection. Mutational analysis of ALDH3A2 gene revealed three missense, one splice site, and one novel stop codon mutation; c.991G>T (p.E331X). Biochemical studies showed decrease of fatty aldehyde dehydrogenase activity. Our results reinforce the distinct clinical, radiological, and biochemical features of ALDH3A2-related SLS which are the clue for targeted molecular testing. Moreover, we present additional unreported clinical findings and a novel mutation thus expanding the phenotypic and mutational spectrum of this rare disorder.
Genetics of Sjögren Larsson Syndrome and a Case
2002
Sjögren Larsson syndrome (SLS) is a rare autosomal disorder that is characterised by congenital ichthyosis, spastic diplegia or qudriplegia and mental retardation. It is caused by the deficiency of the enzyme, fatty aldehyde dehydrogenase (FALDH) that is required for the oxidation of fatty alcohol to fatty acid. The metabolism of leukotrine B4 (LTB4) has also been reported to be defective in SLS patients. The gene, ADLH3A2, encoding for FALDH has been localised at 17p11.2 and mutations in it cause SLS. The worldwide frequency of SLS is reported to be less than 1: 100,000 births but rarely a case has been reported from India. This article reviews the genetic factors in SLS and reports a case of SLS from India, with two similarly affected sibs. The management of SLS including genetic counselling and prenatal diagnostic possibilities are also discussed.
Brain, 2001
Sjögren-Larsson syndrome (SLS) is an autosomal recessively inherited neurocutaneous disorder caused by a deficiency of the microsomal enzyme fatty aldehyde dehydrogenase (FALDH). We report the clinical characteristics and the results of molecular studies in 19 SLS patients. Patients 1-17 show the classical triad of severe clinical abnormalities including ichthyosis, mental retardation and spasticity. Most patients were born preterm, and all patients exhibit ocular abnormalities and pruritus. Electro-encephalography shows a slow background activity, without other abnormalities. MRI of the brain shows an arrest of myelination, periventricular signal abnormalities of white matter and mild ventricular enlargement. Cerebral 1 H-MR spectroscopy reveals a characteristic, abnormal lipid peak. The degree of white matter abnormality in the MRIs and the height of the lipid peak in 1 H-MR spectra do not correlate with the
Sjögren-Larsson syndrome: report of monozygote twins and a case with a novel mutation
The Turkish journal of pediatrics
Sjögren-Larsson syndrome is an autosomal recessive neurocutaneous disease caused by mutations in the ALDH3A2 gene for fatty aldehyde dehydrogenase, a microsomal enzyme that catalyzes the oxidation of medium- and long-chain aliphatic aldehydes fatty acids. We studied three Turkish Sjögren-Larsson syndrome patients with ichthyosis, developmental delay, spastic diplegia, and brain white matter disease. One patient was homozygous for a novel ALDH3A2 mutation in exon 5. The mutation involves the codon 228 (CGC) with the transversion G->A modifying the codon in CAC, leading to the substitution of the original arginine with a histidine (R228H), modifying the stereospecific properties of this region. These results add to the understanding of the genetic basis of Sjögren-Larsson syndrome and will be useful for DNA diagnosis of this disease.