1.
A novel homozygous Ala529Val LMNA mutation in Turkish patients with mandibuloacral dysplasia.
Garg, A, Cogulu, O, Ozkinay, F, Onay, H, Agarwal, AK
The Journal of clinical endocrinology and metabolism. 2005;(9):5259-64
Abstract
CONTEXT Mandibuloacral dysplasia (MAD) is a phenotypically heterogeneous, rare autosomal recessive disorder characterized by mandibular and clavicular hypoplasia, acroosteolysis, delayed closure of cranial sutures, joint contractures, lipodystrophy, and mottled cutaneous pigmentation. MAD patients with type A lipodystrophy with loss of sc fat from the extremities and normal or slight excess in the neck and truncal regions have been previously reported to carry a homozygous Arg527His mutation in LMNA (Lamin A/C) gene. Among those with type B pattern of lipodystrophy with generalized loss of sc fat, we recently reported a patient carrying compound heterozygous mutations in an endoprotease, zinc metalloproteinase (ZMPSTE24), gene that is involved in posttranslational processing of prelamin A to mature lamin A. OBJECTIVE Our objective was to carry out mutational analysis of LMNA in additional patients with MAD and type A lipodystrophy. DESIGN AND SETTING We studied descriptive case reports at a referral center. PATIENTS Subjects were a male and a female patient with MAD who belonged to two pedigrees from Turkey. MAIN OUTCOME MEASURES We assessed genotype-phenotype relationships. RESULTS We now report that both these patients have a novel homozygous missense mutation (c.1586C-->T; c refers to cDNA reference sequence) in LMNA that replaces a well-conserved residue alanine at position 529 to valine. Intragenic single-nucleotide polymorphisms revealed a common haplotype spanning 2.5 kb around the mutated nucleotide in the parents of both the affected subjects, suggesting ancestral origin of the mutation. The female patient had no breast development despite normal menstruation, a phenotype different from that seen in women with MAD and Arg527His LMNA mutation. CONCLUSIONS We conclude that two homozygous missense LMNA mutations involving the arginine 527 and alanine 529 residues cause MAD with subtle variations in phenotype.
2.
Nevo syndrome is allelic to the kyphoscoliotic type of the Ehlers-Danlos syndrome (EDS VIA).
Giunta, C, Randolph, A, Al-Gazali, LI, Brunner, HG, Kraenzlin, ME, Steinmann, B
American journal of medical genetics. Part A. 2005;(2):158-64
Abstract
We report on seven patients affected with Nevo syndrome, a rare, autosomal recessive disorder characterized by increased perinatal length, kyphosis, muscular hypotonia, and joint laxity. Since its first description by Nevo et al. [1974], only a few cases have been reported. Because some of these patients present clinical features similar to those of the kyphoscoliotic type of Ehlers-Danlos syndrome (EDS VIA), an inherited connective tissue disorder characterized by a deficiency of lysyl hydroxylase due to mutations in PLOD1, we studied seven patients with Nevo syndrome, three of whom have previously been reported, and four of whom are new. In the five patients from whom urine was available, the ratio of total urinary lysyl pyridinoline (LP) to hydroxylysyl pyridinoline (HP) was elevated (8.2, 7.8, 8.6, 3.5, and 4.8, respectively) compared with that in controls (0.20 +/- 0.05, range 0.10-0.38), and similar to that observed in patients with EDS VIA (5.97 +/- 0.99, range 4.3-8.1). Six patients were homozygous for a point mutation in exon 9 of PLOD1 causing a p.R319X nonsense mutation, while one patient was homozygous for a large deletion comprising exon 17 of PLOD1. We conclude that the Nevo syndrome is allelic to and clinically indistinguishable from EDS VIA, and present evidence that increased length at birth and wristdrop, in addition to muscular hypotonia and kyphoscoliosis, should prompt the physician to consider EDS VIA earlier than heretofore.