From OMIM
Hereditary amyloidoses are a clinically and genetically heterogeneous group of autosomal dominantly inherited diseases characterized by the deposit of unsoluble protein fibrils in the extracellular matrix. Patients with AMYLD1 typically present with polyneuropathy, carpal tunnel syndrome, autonomic insufficiency, cardiomyopathy, and gastrointestinal features, occasionally accompanied by vitreous opacities and renal insufficiency. In later stages of the disease severe diarrhea with malabsorption, cachexia, incapacitating neuropathy, severe cardiac disturbances, and marked orthostatic hypotension dominate the clinical picture. Death usually occurs 5 to 15 years after onset of symptoms (summary by Hund et al., 2001). Reviews Ando et al. (2005) provided a review of transthyretin-related familial amyloid polyneuropathy. The authors stated that the phenotypes can be classified into neuropathic, oculoleptomeningeal, and cardiac. Adams et al. (2019) reviewed hereditary transthyretin amyloidosis, discussing epidemiology, phenotypic heterogeneity, genetic heterogeneity and its influence on age of onset, pathophysiology, and the success of phase III studies of gene-silencing therapies. Genetic Heterogeneity of Hereditary Systemic Amyloidosis AMYLD2 (105200) is caused by mutation in the fibrinogen A-alpha gene (FGA; 134820) on chromosome 4q31. AMYLD3 (620657) is caused by mutation in the apolipoprotein A-1 gene (APOA1; 107680) on chromosome 11q23. AMYLD4 (105120), or Finnish amyloidosis, is caused by mutation in the gelsolin gene (GSN; 137350) on chromosome 9q33. AMYLD5 (620658) is caused by mutation in the lysozyme gene (LYZ; 153450) on chromosome 12q15. AMYLD6 (620659) is caused by mutation in the beta-2 microglobulin gene (B2M; 109700) on chromosome 15q21.  http://www.omim.org/entry/105210

From MedlinePlus Genetics
Transthyretin amyloidosis is a progressive condition characterized by the buildup of abnormal protein deposits called amyloids (amyloidosis) in the body's organs and tissues. These protein deposits most frequently occur in the peripheral nervous system, which is made up of nerves that connect the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound. Protein deposits in these nerves result in a loss of sensation or in muscle weakness in the extremities (peripheral neuropathy). The autonomic nervous system, which controls involuntary body functions such as blood pressure, heart rate, and digestion, may also be affected by amyloidosis. In some cases, the brain and spinal cord (central nervous system) are affected. Other areas of amyloidosis include the heart, kidneys, eyes, and gastrointestinal tract. The age at which symptoms begin to develop varies widely among individuals with this condition, typically ranging from age 20 to 70.

There are two major forms of transthyretin amyloidosis, which are distinguished by their symptoms and the body systems they affect.

The neuropathic form of transthyretin amyloidosis primarily affects the peripheral and autonomic nervous systems, resulting in peripheral neuropathy and difficulty controlling bodily functions. Impairments to bodily functions can include sexual impotence, diarrhea, constipation, problems with urination, and a sharp drop in blood pressure upon standing (orthostatic hypotension). Some people experience heart and kidney problems as well. Various eye problems may occur, such as cloudiness of the clear gel that fills the eyeball (vitreous opacity), dry eyes, increased pressure in the eyes (glaucoma), or pupils with an irregular or "scalloped" appearance. Some people with this form of transthyretin amyloidosis develop carpal tunnel syndrome, which is characterized by numbness, tingling, and weakness in the hands and fingers.

The cardiac form of transthyretin amyloidosis affects the heart. People with cardiac amyloidosis may have an abnormal heartbeat (arrhythmia), an enlarged heart (cardiomegaly), or orthostatic hypertension. These abnormalities can lead to progressive heart failure and death. Occasionally, people with the cardiac form of transthyretin amyloidosis have mild peripheral neuropathy.

A less common form of transthyretin amyloidosis, called the leptomeningeal form, primarily affects the central nervous system. In people with this form, amyloidosis occurs in the leptomeninges, which are two thin layers of tissue that cover the brain and spinal cord. A buildup of proteins in this tissue can cause stroke and bleeding in the brain, an accumulation of fluid in the brain (hydrocephalus), difficulty coordinating movements (ataxia), muscle stiffness and weakness (spastic paralysis), seizures, and loss of intellectual function (dementia). Eye problems similar to those seen in the neuropathic form of transthyretin amyloidosis may also occur; people with leptomeningeal transthyretin amyloidosis who have these eye problems are said to have the oculoleptomeningeal form.  https://medlineplus.gov/genetics/condition/transthyretin-amyloidosis