Brazilian Nemaline Myopathy Natural History Study: Establishing the Clinical Baseline

Topic:

Clinical Management

Poster Number: 107 S

Author(s):

Cristiane Araujo Martins Moreno, MD, PhD, University of Sao Paulo, Tatiana Ribeiro Fernandes, University of Sao Paulo, Ana Paula Anjos Lança, University of Sao Paulo, Gisele Chagas de Medeiros, PhD, University of Sao Paulo, Eliene Dutra Campos, University of Sao Paulo, Joemir Jábson da Conceição Brito, MD, University of Sao Paulo, Daniel Shoji Hayashi, MD, PhD, University of Sao Paulo, Clara Gontijo Camelo, MD, PhD, University of Sao Paulo, Edmar Zanoteli, MD, PhD, University of Sao Paulo

Background: Nemaline myopathy (NM) is a rare and highly heterogeneous disease defined histologically by the presence of nemaline bodies (or “rods”) within the skeletal muscle fibers. Data regarding the Natural history of the disease is still lacking. Here we present an ongoing baseline data from a Brazilian NM-NHS.
Methods: Patients with NM from a single center in Brazil were included (0-25 years old) and evaluated by a trained neurologist, physiotherapist and speech therapist. They performed motor, respiratory and bulbar functional measures according to patient’s age and capacities. Patients are going to be seen every 6 months (age from 0-17 years old) or annually (>18 years old).
Results and Discussion: Seventeen patients with NM were included; twelve with NEB variants, four with ACTA1 variants and one with KLHL40 variants. Patients were 16 (+-9) years old. Of the 17 patients, even during the gestational period, reduced fetal movements were reported by 6 patients and polyhydramnios by 3. Seven patients presented with neonatal complications, with 6 requiring ventilatory support and 7 requiring a feeding tube within the first 6 months of life. All patients experienced motor delay, and 6 never achieved independent ambulation (walking). Of those who did walk, the mean age of walking acquisition was 24 months. Fourteen patients underwent the MFM32 (Motor Function Measure 32), which showed a performance of 49% in Dimension 1 (D1), 80% in Dimension 2 (D2), and 91% in Dimension 3 (D3). At the time of evaluation, 12 patients were using ventilatory support. Twelve patients underwent the pulmonary function test and showed an average of 42% of predicted function. Most of the patients presented facial weakness and orofacial abnormalities. Twelve patients had dental malocclusion, 14 presented with tongue atrophy, and 15 presented with dysphonia, with of them 4 having speech that was difficult to understand. Fourteen patients performed the slurp test and showed an average time of 26 seconds.
Conclusion: Patients enrolled in this NHS had pronounced symptoms at motor, respiratory and bulbar level. A prospective follow-up, such as this one, is essential for us to better understand the progression of the disease, even in older age groups.