When do you consider genetic testing in patients with suspected hereditary brachial plexopathy?

There are two hereditary disorders associated with brachial plexopathy: 1) Hereditary neuralgic amyotrophy (HNA), which is caused by SEPT9 mutations ~70% of cases, and 2) Hereditary neuropathy with liability to pressure palsies (HNPP), which can manifest as a painless brachial plexopathy especially ...