Author Response: Prospective Natural History Study in 24 Adult Patients With LGMDR12 Over 2 Years of Follow-up: Quantitative MRI and Clinical Outcome Measures

We read with interest the comments by Professor Kawada on our article.¹ As described in the article, all participants were evaluated 3 times within strict 1-year intervals; there were no missed visits or missing data. Furthermore, we defined disease onset as the start of clinical symptoms of limb-girdle muscular dystrophy autosomal recessive type 12 (LGMDR12) and thereby excluded patients with isolated hyperCKemia for increased phenotypic homogeneity.

We noted that LGMDR12 is less frequent and severe in women, as described in the study by Khawajazada et al.² We did not evaluate this in our article because our subjects consisted of 20 men and 4 women, which made the latter group too small for reliable statistical analyses, especially when considering the disease stage subgroups we examined and described in the limitations section. The man to woman ratio in our article was nonetheless quite representative for the general LGMDR12 patient population, and our results would have been similar if only men had been analyzed.

In addition, a wide range in age at onset is very characteristic for LGMDR12, as is represented in our article. We suggest that future studies should attempt to explain the large heterogeneity in disease severity and progression in LGMDR12.