Table 1 Genetic, clinical and myopathological features of EBS-MD patients

1, m

▪ compound heterozygous

▪ exon 19: c.2264_2266delTCT/p.(Phe755del) (in-frame deletion)

▪ exon 24: c.3119_3120delAA/p.(Lys1040Argfs*139) (premature termination codon)

➢ no detectable plectin protein expression

▪ EBS: since birth

▪ myopathy: generalized; predominantly affecting shoulder-girdle and lower leg muscles

▪ dilated cardiomyopathy; ventricular arrhythmias

▪ LM: myopathic pattern; fibers with rubbed-out lesions; desmin-protein aggregates

▪ EM: degenerating myofibrills; autophagic vacuoles (triceps muscle; age at biopsy: 33 years)

2, f [17]

▪ homozygous

▪ exon 32: c.13459_13474dup/p.(Glu4492Glyfs*48) (premature termination codon)

➢ reduced plectin protein expression (full-length and rodless)

▪ EBS: since birth

▪ myopathy: generalized; predominantly affecting proximal muscle groups; facial weakness; marked bilateral ptosis; incomplete external ophthalmoplegia,

▪ mild left ventricular cardiac hypertrophy

▪ bilateral cataracts

▪ brain atrophy with hydrocephalus ex vacuo

▪ LM: myopathic pattern; rimmed-vacuoles; fibers with rubbed-out lesions; desmin-protein aggregates

▪ EM: degenerating myofibrils; cytoplasmic bodies; abnormally shaped mitochondria with paracristalline inclusions; desmin-positive filaments and sub-sarcolemmal protein aggregates

(quadriceps muscle; age at biopsy: 25 years)

3, f [11]

▪ homozygous

▪ exon 31: c.5018_5036del/p.(Leu1673Argfs*64) (premature termination codon)

➢ expression of rodless plectin protein only

▪ EBS: since birth

▪ myopathy: mild neck flexion, shoulder abduction, elbow flexion and hand muscle weakness

▪ inspiratory stridor in the postnatal period due to moderate supraglottic obstruction caused by interarytenoid scarring

▪ LM: myopathic pattern; fibers with rubbed-out lesions; COX-negative fibers; desmin-protein aggregates

▪ EM: not performed

(biceps muscle; age at biopsy 24 years)