201
R
i lo n di truy n
Map 13.2 Di truy n gen l n liên k t NST X
DUCHENNE MUSCULAR DYSTROPHY
What is Duchenne muscular dystrophy?
This is a form of muscular dystrophy.
Causes
•
Mutated dystrophin gene at locus Xp21.
Signs and symptoms
•
Patient falls frequently.
•
Muscle pseudohypertrophy.
•
Fatigue.
•
Muscle fibrosis.
•
Toe walking/difficulty walking.
•
Positive Gower’s test.
•
Muscle weakness.
Investigations
•
DNA testing: confirms mutation of dystrophin gene.
•
Creatine phosphokinase test. Results show increased levels.
•
Muscle biopsy: confirms mutation of dystrophin gene.
•
Electromyography (EMG): analyses muscle destruction.
Treatment
There is no specific treatment for this disease. Prednisolone and creatinine replacement may be considered. Patient will be
wheelchair bound at ~12 years; refer to occupational therapy and physiotherapy. Patient and parent education and support
is essential since this condition is very debilitating and life expectancy is ~25–30 years.
Complications
•
Scoliosis.
•
Respiratory complications and increased risk of respiratory infections.
•
Cardiomyopathy.
•
Osteoporosis.
H I CH NG LESCH–NYHAN
H i ch ng Lesch–Nyhan là gì?
Đây là m t b nh di truy n gen l n liên k t NST X hi m g p, gây tăng acid uric máu
Nguyên nhân
•
Thi u h t HGPRT (hypoxanthine–guanine phosphoribosyltransferase).
Tri u ch ng
•
R i lo n hành vi
•
M t ki m soát cơ.
•
Thi u năng trí tu .
•
Tri u ch ng c a b nh Gout, xem trang 162
•
Hành vi t làm h i mình
Xét nghi m
•
Máu: Công th c máu (FBC), Ure và đi n gi i đ (U&Es), ch c năng gan, creatinine, uric acid, HGPRT.
•
Ch n đoán hình nh: siêu âm phát hi n s i urat không c n quang trên X-quang
Đi u tr
•
Giáo d c ngư i nhà
•
Thu c: allopurinol (làm gi m acid uric máu). V i BN có tri u ch ng th n kinh., tâm th n: Xem xét benzodiazepines
and baclofen.
Bi n ch ng
•
Gout.
•
T làm h i mình
•
S i th n.
MAP 13.2 Di truy n gen l n liên k t NST X (ti p)
Chapter_13.indd 201
08/12/14 6:43 PM
