Proposed diagnostic criteria:

Distal predominant muscle weakness and atrophy in forearm and hand
Involvement of the unilateral upper extremity almost always all the time
Onset between the ages of 10 to early 20s
Insidious onset with gradual progression for the first several years, followed by stabilization
No lower extremity involvement
No sensory disturbance and tendon reflex abnormalities
Exclusion of other diseases (e.g., motor neuron disease, multifocal motor neuropathy, brachial plexopathy, spinal cord tumors, syringomyelia, cervical vertebral abnormalities, anterior interosseous, or deep ulnar neuropathy)
A neurological exam can suggest different motor neuron diseases (such as MMA), but to more confidently distinguish MMA from the diseases it mimics, advanced diagnostic tools are called for. These include exam tools such as magnetic resonance imaging (MRI), and electromyography (EMG) and nerve conduction velocity (NCV) tests. An MRI examination of the neck would typically reveal—for a positive MMA diagnosis—some constriction of the cervical cord and an abnormal forward extension of the neck, ("loss of cervical lordosis"); pressure by the dura on the nerve cord apparently causes the flattening / narrowing. An EMG test reveals loss of the nerve supply, or denervation, in the affected limb without a conduction block (a nerve blockage restricted to a small segment of the nerve).In early stages of the disease MMA may be confused for amyotrophic lateral sclerosis (ALS), cervical spondylotic amyotrophy (CSA), and other challenging neurological diseases, as well as conditions that are minor but that call for very different treatments, such as advanced carpal tunnel syndrome (CTS). Symptoms somewhat differ.
These medications can contribute to bone loss and can increase risk for osteoporotic fractures. Genetic
Maternal body build, lifestyle, and vitamin D status are some of the genetic and epigenetic effects that have been found to affect the BMD, specifically the developmental plasticity.Additionally, other studies have found that race (e.g. Black women have the lowest risk), age (i.e. older age), body mass (i.e. lower weight), and gender (female) play a role in contributing to the risk of osteoporosis. Although the incidence of developing osteoporosis and hip fractures vary between population groups, older age is consistently associated with a higher incidence of fractures due to osteoporosis. Social and nutritional factors
There are several environmental and social factors that can contribute to the risk of developing osteoporosis. Smoking tobacco can increase the risk by decreasing the ability of the intestine to absorb calcium. Caffeine intake and heavy alcohol were also correlated with the decrease in bone density in the elderly population.Without proper intake of vitamin D and calcium, it can increase the risk of osteoporosis in the elderly. These vitamin deficiencies pose as a risk factor, as it can decrease bone mass, decrease calcium absorption, and increase in bone turnover. There are also various medications can that interfere with the absorption of calcium, such as anticonvulsants, diuretics, corticosteroids, immunosuppressive medications, some antibiotics, and NSAIDS.