A 51-year-old caucasian woman presented with a 6 year history of, initially exercise dependent, proximal leg weakness. Her brain MRI showed extensive, predominantly supratentorial white matter changes, that could not be attributed to her known hypertension. She had a single grand mal seizure as a teenager upon photostimulation and suffers from migraine with aura. Her mother was reported to suffer from epilepsy due to traumatic brain injury and her two sisters were said to have skeletal deformities due to use of analgetics during the pregnancies. Our patient's sisters, son and daughter report no neuromuscular complaints. Her serum CK was 200 - 500 U/l, CSF analysis and lab work-up for adult white matter disorders did not reveal abnormalities, but vastus muscle biopsy showed mildly dystrophic changes with an increased fibre size variation, fibre degeneration and regeneration, some fibrosis as well as rimmed vacuoles. Immunohistochemistry showed normal reactivities, including anti-laminin α2 (NCL-MEROSIN) and -α-dystroglycan, but for anti-p62 deposition along rimmed vacuoles. However, anti-laminin α2 western blot showed loss of the 80 kDa band (Millipore MAB1922). Genetic analysis for m.A3243G and m.A8344G point mutations as well as DNAJB6 and NOTCH3 genes gave normal results. In the LAMA2 gene two variants were found, c.2171_2172del and c.2173C > A, the former a known pathogenic mutation, however, in cis. We conclude that this is a case of late onset adult merosinopathy with an affection of the second LAMA2 allele escaping detection so far. In suspected laminin α2 disorders, both, the 300 kD and 80 kD subunit, need to be examined. We did not observe a selective reduction of the 300 kD isoform that has been suggested for milder forms, and hope to be able to examine further family members to ensure that their reported symptoms are indeed unrelated.