Common Congenital Malformations in Chinese
Department of Pediatrics and Medicine Genetics, National Taiwan University, Taipei, Taiwan.
Congenital malformations in Chinese is not quite different from Caucasian, the differences are in the incidence and degree of clinical manifestations.
They consist of chromosomal anomalies, single gene disorders, polygenic disorders, congenital infections et cetra.
The most common ones are different kinds of congenital heart diseases, about one in one hundred newborns, including ventricular septal defect, patent ductus arterious, atrial septal defects, patent foramen ovale, tetralogy of Fallot, coarctation of aorta, double outlet of ventricles, and other rather congenital heart diseases.
The most common chromosomal anomalies among Chinese is Down syndrome, about one in eight hundreds newborns. The incidence is nearly the same as Caucasians. The complications among Chinese Down syndrome including mental retardation, cardio-vascular anomalies, gastrointestinal anomalies are also the same as Caucasiam.
The second most common chromosomal anomalies in Chinese is Klinefelter syndrome, around one in one thousand newborns. There are no major external anomalies. Because in lack of spermatogenesis, there is no tenderness over tests after puberty. They are usually infertile, but the development of in vitro fertilization may give their couple becoming pregnant.
Turner syndrome found one in four thousand Chinese females. Their characteristic are neonatal dorsal edema, web neck, short stature, congenital heart diseases especially coarctation of aorta, and lack of secondary sexual characteristic after puberty.
The final height of Turner syndrome could be increased by treating with recombinant growth hormine, but should be given as early as possible, especially before puberty.
The incidences of other numerical anomalies of either autosomal or sex chromosomal anomalies are nearly the same as the report of Caucasian. The most common structural anomaly of chromosome among Chinese is cat-crying syndrome (cri-du chat), the deletion of the short arm (p arm) of No. 5 chromosome. They have cat-like small crying voice during infancy, but improved by age. They have characteristic facial appearance and severe mental retardation.
The most interesting structural anomalies of chromosome is Fragile-X syndrome. Their incidence among Chinese is one among two thousand, only secondary to Down syndrome among mental retardation population and institutionalized group. Recent molecular studies reveal that it is due to over-repeats of trinucleotide, that is CGG over repeats. The deletions of 15q11-13 results in either Pradder-Willi syndrome or Angelman syndrome due to genomic "imprinting" are also not so rare among Chinese population.
The congenital "Syndrome" result in congenital anomalies among Chinese can be found as may as illustrated in the textbook. They can be due to single gene disorders such as Laurence-Moon-Biedl syndrome, whistling face syndrome (Freeman-Sheldon syndrome), Waardenburg syndrome, Treacher Collins syndrome, Hott-Oram syndrome, Achandroplasia thanatophoric dysplasia, osteogenesis imperfecta. Jeune choracic dystrophy multiple exostosis syndrome, Ellio-van Creveld syndrome (chrondroectodermal dysplasia), chondrodysplasia punctata, Noonan syndrome X-linked hypophosphatemic rickets, anhidrotic ectodermal dysplasia, frontomataplyseal dysplasia, cleidovranial dysoslosis, craniosynostosis syndromes such as apert syndrome, crouzon syndrome, etc.
They can be due to unknown causes (or "sporadic"). Such as Cornelia de Lange syndrome. Rubinstein-Taybi syndrome, Russell-Silver syndrome, Seckel syndrome, Williams syndrome, progeria syndrome, VACTERAL syndrome, et cetra.
It is interesting that some DNA repair defects such as Bloom syndrome are rather rare among Chinese population.
Our policy is that autosomal recessive disorders usually come from consanguinity. Imbreeding is discouraged. Other congenital anomalies, we could try to do our best to save their lifes in order to respect the life.
We try to form various kinds of team, in order to give early intervention, to give them special education and try to teach them to gain some skill to support themselves, and even give contribution to our society.
We consider respect of life and prevent un-treatable congenital anomalies are
our goal. We could like to consider the congenital anomalies from various aspects
including ethics, medical and respect of human life.
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