Charcot-Marie-Tooth disease type 4D (Monarch Disease Ontology identifier MONDO_0011085) (CMT4D) is a subtype of Charcot-Marie-Tooth disease type 4 characterized by a childhood-onset of severe, progressive, demyelinating sensorimotor neuropathy manifesting with distal muscle weakness and atrophy, sensorineural hearing impairment leading to deafness (usually in third decade), severely reduced nerve conduction velocities, and skeletal, especially foot, deformities. Tongue atrophy has also been reported. Also known as: CMT4D, Charcot-Marie-Tooth disease type 4 caused by mutation in NDRG1, Charcot-Marie-Tooth neuropathy type 4D, HMSN Lom type, HMSN, Lom type, HMSN-Lom, HMSN4D, HMSNL.