IllnessMyopathy, nemaline; differential diagnosis

NGS +

In nemaline myopathy, abnormal muscle cells comprise rod-like structures called nemaline bodies. This myopathy mainly affects skeletal muscles throughout the body, most severely in the face, neck, trunk and other proximal muscles of the upper arms and legs. Initially, infants and young children may have difficulty feeding and swallowing, lateron foot deformities, scoliosis and contractures. If the respiratory muscles are affected, life-threatening conditions may result. Clinically, nemaline myopathy is divided into types of decreasing severity: severe congenital, moderate congenital, typical congenital, childhood-onset and adult-onset. There is overlap between the different types. The severe congenital cases do not survive early childhood, such as the Amish type. The most common form is characterized by muscle weakness and feeding problems occuring in infancy, while some patients develop muscle weakness in adolescence. In the adult type, the weakness develops between 20-50 years of age. Nemaline myopathy is usually inherited in an autosomal recessive manner. Most cases of nemaline myopathy are due to mutations in the NEB (50%) or ACTA1 (15-25%) genes. Mutations in each of the other genes account for only a small percentage of cases. Altogether, a negative molecular genetic result cannot exclude the clinical diagnosis.

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6726674/

• Alias: Nemaline myopathy
• Alias: Nemaline rod myopathy
• Allelic: Arrhythmogenic right ventricular dysplasia, familial (FLNC)
• Allelic: Arthrogryposis, distal, type 1A (TPM2)
• Allelic: Arthrogryposis, distal, type 2B4 (TPM2)
• Allelic: Cardiomyopathy, dilated, 1KK (MYPN)
• Allelic: Cardiomyopathy, familial hypertrophic, 26 (FLNC)
• Allelic: Cardiomyopathy, familial restrictive 5 (FLNC)
• Allelic: Cardiomyopathy, familial restrictive, 4 (MYPN)
• Allelic: Cardiomyopathy, hypertrophic, 22 (MYPN)
• Allelic: Charcot-Marie-Tooth disease, DI G (NEFL)
• Allelic: Charcot-Marie-Tooth disease, type 1F (NEFL)
• Allelic: Charcot-Marie-Tooth disease, type 2E (NEFL)
• Allelic: Malignant hyperthermia susceptibility 1 (RYR1)
• Allelic: Myopathy, scapulohumeroperoneal (ACTA1)
• CAP myopathy 1 (TPM3)
• CAP myopathy 2 (TPM2)
• Congenital myopathy 1A, AD, with susceptibility to malignant hyperthermia (RYR1)
• Congenital myopathy 1B, AR (RYR1)
• Congenital myopathy 20 (RYR3)
• King-Denborough syndrome (RYR1)
• Klippel-Feil syndrome 4, AR, with myopathy + facial dysmorphism (MYO18B)
• Myopathy, actin, congenital, with cores (ACTA1)
• Myopathy, actin, congenital, with excess of thin myofilaments (ACTA1)
• Myopathy, congenital, with fiber-type disproportion (TPM3)
• Myopathy, congenital, with fiber-type disproportion 1 (ACTA1)
• Myopathy, distal, 4 (FLNC)
• Myopathy, myofibrillar, 5 (FLNC)
• Nemaline myopathy 1, AD or AR (TPM3)
• Nemaline myopathy 10 (LMOD3)
• Nemaline myopathy 11, AR (MYPN)
• Nemaline myopathy 2, AR (NEB)
• Nemaline myopathy 3, AD or AR (ACTA1)
• Nemaline myopathy 4, AD (TPM2)
• Nemaline myopathy 5, Amish type (TNNT1)
• Nemaline myopathy 6, AD (KBTBD13)
• Nemaline myopathy 7, AR (CFL2)
• Nemaline myopathy 8, AR (KLHL40)
• Nemaline myopathy 9 (KLHL41)
• Nemaline myopathy [Lit.] (RYR1, RYR3)
• Nemaline myopathy [panelapp] (NEFL)