Birth prevalence and pattern of osteochondrodysplasias in an inbred high risk population.
BACKGROUND
Define the pattern and birth prevalence of the different types of osteochondrodysplasias in newborn infants in the United Arab Emirates (UAE) population, which is highly inbred and where termination of pregnancy is not accepted.


METHODS
All infants with a birth weight of 500 gm and above in the three hospitals in Al Ain Medical District of the UAE were studied prospectively over a period of 5 years. For each live birth or stillbirth with suspected skeletal dysplasia, a detailed clinical and radiological examination was carried out. Pregnancy history and information regarding parental age, ethnic origin, family history, and level of consanguinity were obtained and a pedigree was constructed.


RESULTS
Among the 38,048 births during the study period, 36 (9.46/10,000 births) had some type of skeletal dysplasia. Eighteen cases were attributed to autosomal recessive genes (4.7/10,000 births), 10 were due to apparent new dominant mutations (2.62/10,000), five were autosomal dominant type (1.3/10,000) and one was X-linked dominant type (0.26/10,000). In three cases, inheritance was unknown. The most common recessive type of skeletal dysplasia in our series was fibrochondrogenesis (1.05/10,000), followed by chondrodysplasia punctata (0.78/10,000). The birth prevalence rate of skeletal dysplasia doubled in the last 2 years of the 5-year observation period (6.74/10,000 in 1996 vs. 12.86/10,000 in 1999, and 13.45/10,000 in 2000). This increase involved cases caused by new dominant mutations, and occurred mainly in the first half of 1999.


CONCLUSIONS
This prospective study has identified a high birth prevalence of skeletal dysplasia, and risk factors are postulated. These findings represent an accurate birthprevalence figure and a useful baseline for this group of birth defects in the UAE.
Al-Gazali
Lihadh I
LI
Department of Pediatrics, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates. algazali@hotmail.com
Bakir
Mahmood
M
Hamid
Zuhair
Z
Varady
Elizabeth
E
Varghes
Mani
M
Haas
Danialla
D
Bener
Abdulbari
A
Padmanabhan
Rengasamy
R
Abdulrrazzaq
Yousef M
YM
Dawadu
Adekunle
A
Abdulrrazzzaq
Yeusef M
YM
Dawodu
Aden Kula
AK
D000328:Adult; D003241:Consanguinity; D005260:Female; D005313:Fetal Death / Q000453:epidemiology; D005799:Genes, Dominant; D005808:Genes, Recessive; D040181:Genetic Diseases, X-Linked / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D010009:Osteochondrodysplasias / Q000145:classification / Q000453:epidemiology* / Q000235:genetics; D010331:Paternal Age; D015995:Prevalence; D011446:Prospective Studies; D012306:Risk; D014479:United Arab Emirates / Q000453:epidemiology