Familial monomelic amyotrophy: a case report from India

Area of Science:

• Neurology
• Genetics
• Motor Neuron Diseases

Background:

• Monomelic amyotrophy (MMA) is a benign, sporadic lower motor neuron disorder affecting young males, characterized by progressive, self-limiting weakness and muscle wasting in a distal extremity.
• The precise pathogenesis of MMA remains unknown, contributing to diagnostic challenges and limited understanding of its potential genetic underpinnings.

Observation:

• This report details a rare familial occurrence of MMA in a 21-year-old man and his mother, presenting with distinct upper limb involvement and disease duration.
• The index case exhibited left upper limb weakness for 3 years, while his mother presented with right upper limb amyotrophy and weakness spanning 34 years.

Findings:

• This is the first documented instance of familial Monomelic Amyotrophy (MMA) identified at our institute, identified within a cohort of 190 MMA patients diagnosed over 27 years.
• The identification of familial MMA suggests a potential, albeit rare, genetic component influencing the disorder's etiology, contrasting with its predominantly sporadic presentation.

Implications:

• The discovery of familial MMA broadens the understanding of its pathogenesis, suggesting that genetic factors may play a role in a subset of cases.
• This finding underscores the importance of considering family history in the diagnosis of MMA and may guide future research into genetic markers and inheritance patterns.
• Further investigation into familial MMA cases could elucidate specific genetic mutations or predispositions, potentially leading to improved diagnostic criteria and therapeutic strategies.