RESEARCH ARTICLE Clinical and Molecular Study in Congenital Muscular Dystrophy With Partial Laminin a2 (LAMA2) Deficiency Zivana Tezak, 1 Paola Prandini, 2 Marco Boscaro, 2 Alessandra Marin, 2 Joseph Devaney, 1,3 Michael Marino, 3 Marina Fanin, 2 Carlo P. Trevisan, 2 Julie Park, 4 Weslie Tyson, 5 R. Finkel, 6 Carlos Garcia, 7 Corrado Angelini, 2 Eric P. Hoffman, 1 and Elena Pegoraro 2n 1 Research Center for Genetic Medicine, Children’s Research Hospital, Washington, DC; 2 Department of Neurological and Psychiatric Sciences, University of Padova, Padova, Italy; 3 Transgenomic, Inc., Gaithersburg, Maryland; 4 Children’s Hospital of Oklahoma, Oklahoma City, Oklahoma; 5 Children’s Hospital, Denver, Colorado; 6 Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, Pennyslvania; 7 Department of Psychiatry and Neurology, Tulane University Health Sciences Center, New Orleans, Louisiana Communicated by Haig H. Kazazian, Jr. Complete laminin a2 (LAMA2) deficiency causes approximately half of congenital muscular dystrophy (CMD) cases. Many loss-of-function mutations have been reported in these severe, neonatal-onset patients, but only single missense mutations have been found in milder CMD with partial laminin a2 deficiency. Here, we studied nine patients diagnosed with CMD who showed abnormal white-matter signal at brain MRI and partial deficiency of laminin a2 on immunofluorescence of muscle biopsy. We screened the entire 9.5 kb laminin a2 mRNA from patient muscle biopsy by direct capillary automated sequencing, single strand conformational polymorphism (SSCP), or denaturing high performance liquid chromatography (DHPLC) of overlapping RT-PCR products followed by direct sequencing of heteroduplexes. We identified laminin a2 sequence changes in six of nine CMD patients. Each of the gene changes identified, except one, was novel, including three missense changes and two splice-site mutations. The finding of partial laminin a2 deficiency by immunostaining is not specific for laminin a2 gene mutation carriers, with only two patients (22%) showing clear causative mutations, and an additional three patients (33%) showing possible mutations. The clinical presentation and disease progression was homogeneous in the laminin a2-mutation positive and negative CMD patients. Hum Mutat 21:103–111, 2003. r 2003 Wiley-Liss, Inc. KEY WORDS: laminin a2; LAMA2; congenital muscular dystrophy; CMD; autosomal recessive; SNP; extracellular matrix DATABASES: LAMA2 – OMIM: 156225; GenBank: XM_011387, AH003690 INTRODUCTION Laminin-2 is an extracellular matrix, heterotrimeric protein containing two light chains (b1 and g1), and one muscle-specific heavy chain (a2) (LAMA2; MIM# 156225) [Timpl et al., 1979; Ehrig et al., 1990; Voulteenaho et al., 1994]. Laminin-2 in skeletal muscle provides a link between the extracellular matrix and the membrane cytoskeleton, mediated by its specific membrane receptors, dystroglycan and integrin a7b1 [Campbell and Kahl, 1989; Wewer and Engvall, 1996; Vachon et al., 1997]. Complete laminin a2 deficiency, detected in muscle biopsy using immunohistochemistry [Tome’ et al., Received 27 June 2002; accepted revised manuscript 24 October 2002. n Correspondence to: Elena Pegoraro, M.D. Ph.D., Department of Neurological and Psychiatric Sciences, University of Padova, via Giustiniani 5,35128 Padova, Italy. E-mail: elena.pegoraro@unipd.it Grant sponsor: NIH (NINDS); Grant number: RO1 2952; Grant sponsor: University of Padova; Grant number: 1462; Grant spon- sor: Telethon; Grant number: TF0003Y019; Grant sponsor: MURST; Grant number: 2001068328001. ZivanaTezak and Paola Prandini contributed equally to this work. DOI: 10.1002/humu.10157 Published online in Wiley InterScience (www.interscience.wiley. com). r r2003 WILEY-LISS, INC. HUMAN MUTATION 21:103^111 (2003)