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Congenital malformations—Gross structural defects. Teratology —study of birth defects and their causes. Teratogens – factors causing abnormalities. 1. Rubella - heart defects, deafness, cataract, glaucoma. 2. Cytomegalovirus - microcephaly,blindness, M.R.
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Congenital malformations—Gross structural defects Teratology—study of birth defects and their causes. Teratogens– factors causing abnormalities. 1.Rubella- heart defects, deafness, cataract, glaucoma. 2.Cytomegalovirus- microcephaly,blindness, M.R. 3.X-rays- microcephaly, spina bifida, cleft palate, limb defects.
Important drugs which cause malformations • Thalidomide– limb defects, heart malformations. • Aminopterin - anencephaly, hydrocephaly, cleft lip • Phenytoin- Fetal hydantoin syndrome, M.R. • Trimethadione- cleft palate, heart defects, urogenital and skeletal malformations.
Lithium- heart malformations • Amphetamines- cleft lip and heart defects. • Warfarin - chondrodysplasia, microcephaly. • LSD(lysergic acid)- limb and CNS defects. • Alcohol- fetal alcohol syndrome, heart defects. • Maternal diabetes- variety of malformations- heart and neural tube defects most common.
Ethisterone and norethisterone- fused labia, musculinization of female genitalia, clitoral hypertrophy Diethylstilbestrol(DES)- malformations of uterus, uterine tubes, upper vagina, malformed testes
Fetal Hydantoin Syndrome–Phenytoin abnormalities: craniofacial defects, nail and digital hypoplasia, growth abnormalities, mental deficiency.Caudal regression syndrome- skeletal defects consisting of partial and complete agenesis of sacral vertebrae in conjunction with hind limb hypoplasia which mainly occurs with maternal diabetes.
Trisomy 21 – Down’s syndrome • High incidence in elderly pregnant primi mothers. • Features- mentally retarded • congenital heart defects • simian creases in the hands
Trisomy 17-18Features – M.R, congenital heart defects,low-set ear. Trisomy 13-15 M.R, congenital heart defects, deafness, cleft lip and palate, eye defects
Klinefelter’s syndromeXXY type- 47 chromosomesfound in males.Features- sterility, testicular atrophy, gynecomastia.
Turner's syndrome • XO-45 chromosomes, found in females. • Absence of ovaries (Gonadal dysgenesis). • Webbed neck, skeletal deformities, M.R.
Structural abnormalities • In some cases the broken piece of a chromosome is lost and infants with partial deletion of a chromosome are abnormal. • CRIDU CHAT SYNDROME- short arm of chromosome 5( partial deletion of 5th chromosome). • Features- microcephaly , micrognatha, M.R. and high pitched cat like cry or voice.