Acquired non-compaction in integrin-myopathy

Letter to the Editor With interest we read the article by Esposito et al. about a female child with myopathy and left ventricular hypertrabeculation / noncompaction (LVHT) carrying a mutation in two different genes, the integrin-α7 gene and the myosin heavy chain 7B gene (MYH7B) [1]. We have the following comments and concerns. The authors mention in the discussion that MYL2 and MYL3 mutations were found in patients with LVHT [1]. Among the 5 papers cited to corroborate this statement Budde et al. [2] did not look for MYL2 or MYL3 mutations and Klaassen et al. [3] and Probst et al. [4] definitively state that no mutations in MYL2 or MYL3 were found. Hoedemaekers et al. 2010 [5] tested for MYL2 and MYL3 but do not mention a mutation in these genes in their results either. Walsh et al. 2010 [6] is not an original paper but a review about MYH7 mutations. LVHT has not only been found in association with mutations in the TAZ, DTNA, ZASP, lamin A/C, MYH7, ACTC1, TNNT2, TNNI3, MYBPC3, and TPM1 genes but also in association with mutations in the dystrophin, DMPK, ZNF9, LAMP2, GAA, mtDNA, AMPD1, GBE1, RYR1, COL7A1, PMP22, MMACHC, beta-globin, and DNAJC19 genes [Finsterer et al., submitted]. The index patient underwent echocardiography at age 1 month but LVHT was diagnosed not before the next echocardiographic examination at age 17 months. Which is the reason why LVHT was not detected at the initial examination? Was LVHT missed because of poor image quality, absent awareness of the pathology, ignoring the abnormality, left ventricular hypertrophy at the initial investigation, severe dilation of the left ventricle, or did LVHT truly develop during the period between the two examinations (acquired LVHT)? Did the authors review the initial echocardiographic examination? Did the presence of a patent arterial duct and patent foramen ovale prevent LVHT from being diagnosed at the initial examination?