204
R
i lo n di truy n
Map 13.4 Di truy n gen l n NST thư ng
FAMILIAL ADENOMATOUS POLYPOSIS (FAP)
What is FAP?
This is an autosomal dominant condition that causes
thousands of polyps to develop in the large intestine.
It predisposes patients to colon cancer.
Causes
•
Mutation in the APC gene on chromosome 5.
Signs and symptoms
•
Blood in stool.
•
Signs of malignancy, see page 48.
Investigations
See page 48.
•
Genetic testing and colonoscopy are diagnostic.
Treatment
•
Surgical resection of the affected bowel
is the treatment of choice.
Complications
•
Colon cancer.
EHLERS–DANLOS SYNDROME
What is Ehlers–Danlos syndrome?
This is a type of connective tissue disorder that
results from defective collagen.
Causes
•
Defect in type I and type III collagen synthesis.
Signs and symptoms
Remember these as HBO:
•
Hyperextension.
•
Bruise easily.
•
Osteoarthritis (early onset).
Investigations
•
Collagen gene mutation testing.
•
Skin biopsy for collagen typing.
•
ECHO for valvular heart disease and
aortic dilation.
MAP 13.4 Di truy n
gen tr i NST thư ng
B NH HUNTINGTON
B nh Huntington là gì?
Là m t b nh thoái hóa th n kinh, di truy n gen tr i NST thư ng
Nguyên nhân
•
B t thư ng gen huntingtin n m trên NST 4.
•
D n đ n l p l i chu i (CAG)n
•
Chu i (CAG)n l p l i càng dài, kh i phát b nh càng s m
Tri u ch ng
•
Kh i phát kho ng 35 tu i
•
Gi m kh năng ph i h p v n đ ng ti n tri n
•
Múa gi t
•
Suy gi m nh n th c
•
Thay đ i nhân cách
Xét nghi m
•
Xét nghi m gen đ kh ng đ nh ch n đoán
Đi u tr
•
Giáo d c ngư i nhà. Tư v n di truy n
•
Thu c: Không có đi u tr đ c hi u. Đi u tr các bi n ch ng
Bi n ch ng
•
Co gi t
•
Suy gi m trí nh
•
Khó nu t
•
Tr m c m
•
Ch ng lo âu
Treatment
•
Conservative: patient education.
•
Medical: there is no specific treatment
for this condition. Manage complications.
Complications
•
Valvular heart disease.
•
Joint deformities, e.g. osteoarthritis
and scoliosis.
•
Anal prolapse.
•
Complications during pregnancy.
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