Failure to thrive ... 2

Other reasons ... 2.95

Total ... 100

Table (7): Reasons of referral for cytogenetic study of postnatal cases.

Other causes of referral included prolonged neonatal jaundice, persistent fever, recurrent infections, obesity, hypothyroidism, dry skin, and delayed puberty.

Indication: ... Percentage

Advanced maternal age ... 57.9

Positive triple test ... 31.58

Abnormal U/S ... 5.26

Previous DS ... 5.26

Total ... 100

Table (8): Reasons of referral for cytogenetic study of prenatal cases:

Discussion:

Down syndrome (DS) is perhaps the oldest condition associated with mental retardation and the most common genetic cause of developmental disability. It was the first chromosomal aberration described in man and the most frequent autosomal anomaly. The first clinical description of the disease appears to be Seguin's, in 1846, under the name of furfuraceous idiocy (1). The English physician, John Langdon Haydon Down, wrote in 1866 the clinical description of the condition that was subsequently given his name. The term (mongol), (mongloid), and (mongolism) were widely adopted and used by professionals until about 30 years ago, when representatives of the Mongolian People Republic informally complained to the World Health Organization. Nowadays, DS is the preferred name (2).