What are the signs and symptoms of Charcot-Marie-Tooth disease type 1A? CMT1 is generally slowly progressive over many years. However, affected individuals often experience long periods without any obvious deterioration or progression. Occasionally, individuals show accelerated deterioration of function over a few years. Nerve conduction velocities (NCVs) tend to slow progressively over the first two to six years of life, but they appear to remain relatively stable throughout adulthood. Worsening of signs and symptoms tends to be slow in the second to fourth decades of life. It remains to be confirmed whether, and to what extent, there is clinical and electrophysiological disease progression in affected adults; two studies of adult with CMT1A have shown conflicting results. Authors of one study reported disease progression over time (23 years on average), while authors of another study found that both patients and controls (individuals without the condition) had a similar decline of strength and of electrophysiological findings. The findings in the latter study suggested that the decline in adulthood in affected individuals may reflect a process of normal aging rather than on-going active disease. Any major changes in the pace of progression may warrant consideration of additional acquired, or possibly independently inherited forms, of neuromuscular diseases. The severity of signs and symptoms of CMT1A can vary greatly among affected individuals. Individuals who have questions about their own specific signs and symptoms and how they may relate to progression of CMT should speak with their health care provider. The Human Phenotype Ontology provides the following list of signs and symptoms for Charcot-Marie-Tooth disease type 1A. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Areflexia - Autosomal dominant inheritance - Cold-induced muscle cramps - Decreased motor nerve conduction velocity - Decreased number of peripheral myelinated nerve fibers - Distal amyotrophy - Distal muscle weakness - Distal sensory impairment - Foot dorsiflexor weakness - Hammertoe - Hearing impairment - Heterogeneous - Hypertrophic nerve changes - Hyporeflexia - Insidious onset - Juvenile onset - Kyphoscoliosis - Myelin outfoldings - Onion bulb formation - Pes cavus - Segmental peripheral demyelination/remyelination - Slow progression - Steppage gait - Ulnar claw - Variable expressivity - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.