INSTRUCTION

Examine this patient's legs.

SALIENT FEATURES

History

· See Case 55 (p. 164).

· Ask about a family history of similar weakness.

Examination

· Wasting of muscles of calves and thighs which stops abruptly, usually in the lower third of the thigh, and is described as 'stork'

or 'spindle' legs, 'fat bottle' calves and 'inverted champagne bottles'.

· Pes cavus, clawing of toes, contractures of the Achilles tendon.

· Weakness of dorsifiexion.

· Absent ankle jerks, plantars are downgoing or equivocal.

· Mild sensory impairment or no sensory impairment or no sensory loss soma palients have decreased responses to pain in the

stocking distribution.

Proceed as follows:

· Feel for lateral popliteal nerve thickening (seen in some cases only).

· Look at the hands for small muscle wasting and clawing.

· Tell the examiner that you would like to:

-Know whether there is a family history of disease.

-Look for enlarged greater auricular nerves.

-Examine the spine for scoliosis.

- Examine the gait (high-stepping gait of foot-drop).

Note. There are two distinctive clinical features of this disease:

1. The muscular atrophy begins in the distal portions of the affected muscles in the lower and upper limbs, unlike the global

atrophy of motor neuron disease or muscular dystrophy. The atrophy then creeps upwards, involving all muscles.

2. Second, the degree of disability is minimal in spite of marked deformity.

DIAGNOSIS

This patient has 'inverted champagne bottle' legs with sensory neuropathy (lesion) which is due to hereditary Charcot-Marie-Tooth

disease (aetiology). She has severe foot-drop and requires calipers (functional status).

ADVANCED-LEVEL QUESTIONS

What is the mode of inheritance?

Both autosomal dominant and recessive inheritances are seen in different families. The responsible gene is usually located on the

short arm of chromosome 17 (Ann Neurol 1992; 31: 570; N Engl J Med 1993; 329: 96-101) and less often shows linkage to

chromosomes I or X. In hereditary motor sensory neuropathy (HMSN) type I with dominant inheritance, the locus is on the long arm

of chromosome 1.

What are the three recognized forms?

· HMSN type I - a demyelinating neuropathy (marked slowing of conduction in motor nerves; absent deep tendon reflexes).

· HMSN type Il - an axonal neuropathy (little or no slowing of nerve conduction; normal deep tendon reflexes).

· Distal spinal muscular atrophy.

What other uncommon features may these patients have?

Optic atrophy, retinitis pigmentosa, spastic paraparesis.

In which other condition is pos cavus seen?

Friedreich's ataxia.

What is the natural history of the disease?

The disease usually arrests in middle life.

How does the forme fruste of the disease manifest?

The forme fruste may be seen in family members of patients with Charcot-Marie-Tooth disease and manifests as pes cavus and

absent ankle jerks.

Mention other hereditary neuropathies.

· Roussy-Ldvy syndrome (where features of progressive muscular atrophy may be combined with tremor and ataxia).

· Hereditary amyloidosis.

· Refsum's disease (phytanic acid accumulates in the central and peripheral nervous systems).

· Fabry's disease (where there is a deficiency of o~-galactosidase).

· Tangier disease.

· Bassen-Kornzweig disease (abetalipoproteinaemia, absence of low density lipo-proteins and vitamin E deficiency).

· Metachromatic leukodystrophy (where galactosyl sulphatide accumulates in the central and peripheral nervous systems).

Mention a few conditions that Charcot is credited with having described for the first time.

· Ankle clonus.

· Tabes dorsalis and Charcot's joints.

· Multiple sclerosis.

· Peroneal muscular atrophy.

· Multiple cerebral aneurysms, called Charcot-Bouchard aneurysms.

· Hysteria.

The syndrome was originally described by J.M. Charcot (1825-1923) and P. Marie (1853-1940) in 1886 at the Saltp~triere in Paris,

and independently by H.H. Tooth at St Bartholomew's Hospital and the National Hospital for Nervous Diseases, Queen Square,

London, at the same time. P. Marie was a world-famed neurologist. He published extensively on aphasia. He succeeded Charcot's

lineage of Raymond, Brissaud and Dejerine at the SaltpOtribre in 1918.