CONGENITAL MUSCULAR DYSTROPHY

• INTRODUCTION:-
→ Congenital muscular dystrophy (CMD) refers to a group of muscular dystrophies that become apparent at or near birth. Muscular dystrophies in general are genetic, degenerative diseases primarily affecting voluntary muscles.
→ Congenital muscular dystrophies are autosomal recessively-inherited muscle diseases.

• SIGN / SYMPTOMS:-
→ CMD will display some progressive muscle weakness or muscle wasting (atrophy), although there can be different degrees and symptoms of severeness of progression. The weakness is indicated as hypotonia, or lack of muscle tone, which can make an infant seem unstable.
→ Children may be slow with their motor skills; such as rolling over, sitting up or walking, or may not even reach these milestones of life. Some of the more rarer forms of CMD can result in significant learning disabilities.

Ptosis

Ptosis

• CLASSIFICATION:-
(1) CMD with brain-eye – also called muscle-eye-brain disease is a rare form of congenital muscular dystrophy (autosomal recessive disorder) causing a lack of normal muscle tone which can delay walking due to being weak, also paralysis of eye muscles and intellectual disability
(2) CMD with adducted (drawn inward) thumbs –  a rare form of CMD causing permanent shortening of the toe joints and lack of muscle tone which can delay walking due to the individual being weak.Child have may mild cerebellar hypoplasia in some cases.
(3) CMD/LGMD without MR – first years of a newborn begins with weakness, which affects motive skills, walking can be accomplished in adolescence, deformity and rigidity of joints. The joints, neck and spine; progressive cardiomyopathy at the early ages; cardiac rhythm abnormalities may be present
(4) CMD/LGMD with MR – weakness and deformity and rigidity joints present at birth, poor muscle tone, slowly progressive; individuals may present with cerebellar cysts (or cortical problems), microcephaly may be present as well. Abnormal flexibility might occur, spinal curvature possible.
(5) Large related CMD – at the beginning of the newborn period, the issues the infant receives are; poor muscle tone and weak motor function; the individual will present with mental retardation and the structure of the brain will likely be abnormal.
(6) CMD with cerebellar atrophy – severe cerebellar hypoplasia, poor muscle tone, delayed in motor milestones, lack of coordination in motive skills, difficulty speaking, involuntary movements and some intellectual disability. Furthermore, muscle biopsy does not reveal any deficiency.
(7) Walker–War burg syndrome –  low muscle tone at birth or during early infancy; small muscles; the majority of affected children do not live more than 3 years of age. Eye structure problems are present, with accompanying visual impairment.
(8) CMD with primary laminin-a2 (merosin) deficiency (MDC1A) – intellect in such individuals is unaffected, proximal muscle weakening and rigid spine are present along with respiratory involvement (with disease progression).
(9) CMD with spinal rigidity –  present at birth can have poor muscle tone and weakness, reduced respiratory capacity, muscles could be deformed, beginning early ages stabilization or slow decline spinal rigidity, limited mobility to flex the neck and spine, spinal curvature and progressing deformity and rigidity joints, minor cardiac abnormalities, normal intelligence.
(10)CMD with lamina abnormality – with in the first year the infant is weak, individual may have problems later lifting arms and head. May need nasogastric tube, limb weakness and elevated serum creatine kinase.
(11)Fukuyama CMD – -in western countries this type of CMD is rare but is common in Japan. The effects this disease has on infants is spectrum of severity, weakness in muscle tone within first year, some infants may achieve some walking, have deformity and rigidity joints, spinal curvatures, seizures, eye involvement and intellectual disability.
(12)Merosin-deficient CMD –  present at birth weakness in muscle tone, spectrum of severity; may show hypotonia, and poor motor development. Most individuals have periventricular white matter problems.
(13)Merosin-positive CMD –  some forms of merosin-positive CMD are: Early spinal rigidity, CMD with muscle hypertrophy, CMD with muscle hypertrophy and respiratory failure.
(14)Ullrich congenital muscular dystrophy – present at birth is weakness, poor muscle tone, will have some deformity and rigidity joints, some joints will have excessive flexibility, spinal rigidity, curvature, respiratory impairment, soft skin, normal cardiac function and normal intelligence.

• DIAGNOSIS:-
→ Lab study (CK levels)
→ MRI (of muscle, and/or brain)
→ EMG
→ Genetic testing
→ Muscle biopsy

MANAGEMENT:-
→ The American Academy of Neurology recommends that the individuals need to have monitoring of cardiac function, respiratory, and gastrointestinal. Additionally it is believed that therapy in speech, orthopedic and physical areas, would improve the persons quality of life.
→ While there is currently no cure available, it is important to preserve muscle activity and any available correction of skeletal abnormalities (as scoliosis). Orthopedic procedures, like spinal fusion, maintains/increases the individuals prospect for more physical movement.

AFOs

AFO

• PROGNOSIS:-
→ The condition is usually fairly stable as far as the muscle power in the legs and arms is concerned, and often the child appears to gain strength in the first decade of life. In several forms of congenital muscular dystrophy, the acquisition of new skills over time is possible, although some motor difficulties will always be present, depending on however the condition was at presentation.
→ In many congenital muscular dystrophy sub types, muscle weakness can increase with time and can lead to respiratory problems. This may happen in children of various ages and is potentially a very serious complication which, if not recognized, can be life threatening.
→ The severity of this condition varies greatly from person to person. As the severity varies even within the same form of congenital muscular dystrophy, it is important not to assume that certain motor developments will or will not take place, but rather to work with children so they can achieve the goals which are within their ability.
Some children will walk, but sometimes this can be delayed until the age of five or older.
→ Leg splints are often used to assist a child to walk. Some children who have achieved independent walking may lose this ability later on because, as they grow older and heavier, the muscles are unable to cope with a greater strain. Other children may not be able to walk at all.
→ The presence and the severity of other problems depend on the subtype of congenital muscular dystrophy. Some features, however, are generally found in many children with congenital muscular dystrophy, irrespective of the subtype.

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