Clinical indications for karyotype

Question 1

What is karyotyping

Answer 1

Study of the individual chromosomal complement to detect chromosomal abnormalities.

Question 2

Limit of detection for karyotyping

Answer 2

5-10Mb

Question 3

Clinical indication for karyotype during perinatal period

Answer 3

• Still birth (chromosomal disease suspected)

- Neonatal period (dysmorphic syndrome or ambiguous genitalia)

Question 4

Clinical indication for karyotype during childhood/adolescence

Answer 4

• Pyscho motor retardation (Klinefelter)
• Dysmorphism/ visceral anomalies
• Unexplained short stature (Turners)
• Hypogonadism (Klinefelter, Turners)

Question 5

Clinical indication for karyotype for adults

Answer 5

• Parents of a child with a chromosomal abnormality
• Sterility workup (after endocrine and gynaecological factors excluded)
• More than 2 spontaneous miscarriages (possible carrier of balanced translocation)

Question 6

Clinical indication for karyotype during pregnancy

Answer 6

• Advanced maternal age
• Previous pregnancy/still birth with chromosomal abnormality
• Balanced chromosomal rearrangement or mosaicism in one parent
• Abnormal maternal serological screening test
• Abnormal foetal ultrasound

Question 7

Clinical indication for karyotype for acquired disease

Answer 7

-De novo chromosomal anomalies in tumour cells (normal constitutional karyotype.