mcq

Theme : Diagnosis of chromosomal disorders
A. Di -George Anomaly B. Fragile X C. Karyotype 45XO D. Karyotype 46XX E. Karyotype 47XYY F. Klinefelter syndrome G. Triploidy H. Trisomy 9 I. Trisomy 18 J. Trisomy 21
For each of the following descriptions of clinical abnormalities choose the single most likely genetic disorder from the list of options.
1) A 13 year old boy with learning difficulties, undescended testicles and gynaecomastia.		F. Klinefelter syndrome
Note: Klinefelter syndrome (XXY). Individuals with Klinefelter’s usually have learning difficulties. Phenotypically they are relatively tall and slim individuals with small penis and testicles, gynaecomastia and infertility.
2) Gross foetal oedema, a cystic hygroma and ultrasound appearances of female foetus.		C. Karyotype 45XO
Note: Turner’s syndrome (45XO) affects females. Features include short stature and gonadal agenesis. Ultrasound scan of the foetus in the utero may confirm lymphoedema. Other features include a webbed neck, a broad shield like chest, wide spaced nipples and cubitus valgus. Cardiac anomalies are common in Turner’s syndrome the most common being a bicuspid aortic valve and coaptation of the aorta. Renal anomalies such as horse shoe kidneys are often seen.
3) A cardiac abnormality in a child with immuno deficiency and mild – moderate learning difficulties.		A. Di -George Anomaly
Note: Di -George syndrome, which is a defect of development of the thymus, parathyroid as well as great vessels. They tend to have characteristic facies with short palpable fissures, micrognathia and a short philtrum. They have reduced cellular immunity and hypoparathyroidism leads to hypocalcaemia and seizures. Cardiac anomalies are also common for example aortic arch defects.