A patient with Ehlers-Danlos syndrome type VI is a compound heterozygote for mutations in the lysyl hydroxylase gene.

Abstract

In the present study, we have isolated and sequenced the complementary DNAs of two mutant alleles for lysyl hydroxylase (LH) in fibroblasts from one patient (AT750) with EhlersDanlos syndrome type VI (EDS VI). We have identified a putative mutation in each allele which may be responsible for the patient's decreased LH (normalized to prolyl hydroxylase) activity (24% of normal). Intermediate levels of LH activity were measured in the patient's parents, who are clinically normal (father 52%; mother 86%). After the cloning of cDNAs and amplification by PCR, sequence analysis revealed two equally distributed populations of cDNAs for LH in the AT750 cell line. Each allele revealed different but significant changes from the normal sequence. In one allele (allele 1), the most striking change was a triple base deletion that would result in the loss of residue Glu532. The most significant difference in the other allele (allele 2) was a G -A change which would produce a Gly678 -> Arg codon change in a highly conserved region of the enzyme. Restriction analysis identified that allele 1 was inherited from the proband's mother and allele 2 from the father. This study represents the first example of compound heterozygosity for the LH gene in an EDS VI patient, and it appears that there is an additive effect of each mutant allele on clinical expression in this patient. (J. Clin. Invest. 1994.

Cloning and characterization of a third human lysyl hydroxylase isoform

“…Enzyme Activity Assays. Lysyl hydroxylase activity was assayed by a procedure based on the hydroxylation-coupled decarboxylation of 2-oxo [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]glutarate with 0.75 mg͞ml of (Ile-Lys-Gly) 3 as the peptide substrate (19). K m values were measured as described (6,19), the pooled soluble fractions of the cell homogenate being used as the source of enzyme.…”

“…The NP-40 and glycerol buffer extracts were analyzed for lysyl hydroxylase activity with an assay based on hydroxylationcoupled decarboxylation of 2-oxo [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]glutarate with the synthetic peptide (Ile-Lys-Gly) 3 as a substrate (19). The NP-40 buffer extract, but not the glycerol extract, was found to give a high 2-oxo [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]glutarate decarboxylation rate even in noninfected cells (Table 1).…”

“…Several mutations in the lysyl hydroxylase gene have recently been characterized in families with this disease (10)(11)(12)(13)(14)(15). One interesting aspect of EhlersDanlos syndrome type VI is that the deficiency in hydroxylysine shows a wide variation between tissues (1,8).…”

Systematic analysis of molecular and physiological synergic effects of iron, manganese and copper on connective tissue

“…Ги-дроксилирование коллагена поддерживается лизилгидроксилазами, и мутации в соответству-ющих генах приводят к таким формам дисплазии, как болезнь Элерса-Данлоса [17,19] и метаболи-ческим нарушениям костной ткани [18].…”

Cloning and Characterization of a Novel Human Lysyl Hydroxylase Isoform Highly Expressed in Pancreas and Muscle

“…The complete cDNA-derived amino acid sequence has been reported for the enzyme from chick (9), human (10,11), and rat (12). The enzyme has also been characterized at the genomic level (7), and the first mutations in the lysyl hydroxylase gene have been characterized in patients with type VI of the Ehlers-Danlos syndrome (EDSVI) 1 (13)(14)(15)(16)(17).…”