Surgical Challenges and Dilemmas in Treating Children with Congenital Nemaline Myopathy (TNNT1 Mutation)

Introduction: Congenital Nemaline body (NEM) myopathies are a heterogeneous group of hereditary myopathies. Patients typically present with congenital proximal muscle weakness and hypotonia. Respiratory weakness is often a major concern while intelligence is usually unimpaired. There are five known subtypes, differing in genetic/molecular findings and in the clinical manifestation. Subtype one TNNT1 is rare, described in the Amish population, and lately also in a group of patients originating in Hebron. The "Hebron"` group of patients manifests with severe clinical manifestation mainly respiratory and musculoskeletal. In this study we aim to bring awareness to this special group of patients, and treatment dilemma`s.

Patients: 15 patients were diagnosed with the TMMT1 "Hebron" mutation, 8 males 7 females. Six are relatives - five siblings (2 from one family and 3 from another), and three first degree cousins. Patients ages range from 11 months to 12 years, with an average age of 5 years and 10 months. Six are deceased, all from cardio-respiratory failure, at an average age of 6 years.

Results: All but one (the parents refused) are ventilated with tracheostomy.

All have severe rigid contractures of limbs, severe kyphoscoliosis and chest deformity (pectus carinatum). 2 patients were treated for DDH at early age including reduction under anesthesia. one patient was operated at early age for clubfoot release. 3 patients were operated to release contractures at a later stage and after genetic diagnoses were done.

Because of the severe spine deformities these children suffer from, there were attempts to treat with different kinds of braces. Because of the combined anatomic deformities - pectus carinatum and severe progressive kyphoscoliosis - that eventually caused a major pressure on the lungs and trachea, surgical interventions were planned in several cases. So far, only one patient underwent MAGEC procedure.

Conclusion: This group of patients diagnosed with a rare myopathy, manifested with severe manifestations, influencing greatly their quality of life. Questions are raised concerning timing and modalities of conservative and surgical treatments in this group with short life expectancy.