CLUSTERING AND
PHENOTYPIC VARIABILITY OF TRISOMY-18 IN KUWAIT
Al-Sawan RMZ*, Soni AL*, Saleh QA*, Krishna Murthy DS**
*Farwaniya Hospital, Kuwait; **
Maternity Hospital, Kuwait
Objective: Trisomy-18 (T-18) is the
second most common trisomy in man with incidence of 3 in 10000
livebirths(LB).More than 130 different abnormalities have been noted with
T-18. Clinical features may vary in frequency from place to place. The
present study highlights varying incidence and phenotype of T-18 in Kuwait
having mixed population of Arabs and Asians.
Methods: Over a period of 9 years,
all liveborn babies were examined shortly after birth for any features of
T-18 and chromosomal study was carried out in all using standard
techniques. Relevant investigations done in all cases. Parents’ chromosomal
study was done in proved T-18 cases.
Results: Total 16 cases of T-18
were diagnosed, giving an incidence of 2.5 per 10000 LB. Annual incidence
varied from 0 to 8.5 per 10000 LB; Clustering was seen in the year
1998(6/16 cases) and 1993 &1999(3/16) as well as in the months of
Feb.(4/16) & Jan.(3/16). Sex ratio, maternal age, nationality,
consanguinity, gestational age, birth wt and mode of delivery were not
significantly different. The features described very rare in literature were
found in16-25 % cases namely gum hyperplasia, webbing of neck, hemivertebra
& arthrogryposis. The features reported more common like single
umbilical artery, polyhydramnios & hernias; were seen less frequently.
Conclusions:
Clustering of cases indicate a significant role of environmental factors in
the etiology of T-18.The different phenotype might indicate different
population with different environment in Kuwait compared to other
places.