Figure 3. .

Point mutations in HCCS in two patients with MLS. A–C, Photographs of patients MS1 and MS2. A, Linear skin defects located on the face and neck of patient MS1 at birth. B, Microphthalmia of the right eye and bilateral sclerocornea of patient MS1 at age 4 years. Linear skin defects have completely disappeared. C, Patient MS2, at age 8 years, with bilateral microphthalmia and sclerocornea. No linear skin defects were noted at birth. D, Sequence electropherograms of part of HCCS exons from genomic DNA of patients MS1 and MS2. Nucleotide triplets and encoded amino acids are indicated. Patient MS1 is heterozygous for the c.589C→T mutation (p.R197X) (left panel) in exon 6, whereas the heterozygous mutation c.649C→T (p.R217C) (right panel) in exon 7 was found in patient MS2. E, Partial amino acid–sequence alignment of heme lyases from various species. The position of amino acids is given. Evolutionarily conserved residues are shown in bold. The invariant arginine at position 217, which is altered to cysteine in patient MS2, is shaded in gray. HCCS₁ indicates specificity of the heme lyase for cytochrome c₁. Hs = Homo sapiens; Mm₁ = Mus musculus; Rr = Rattus norvegicus; Cf = Canis familiaris; Pt = Pan troglodytes; Mm = Macaca mulatta; Bt = Bos taurus; Ca = Candida albicans; Sc = S. cerevisiae; Sp = Schizosaccharomyces pombe; Nc = Neurospora crassa; Ce = Caenorhabditis elegans.