1. 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.

2. 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.

4. 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.

5. Ethisterone and norethisterone- fused labia, musculinization of female genitalia, clitoral hypertrophy Diethylstilbestrol(DES)- malformations of uterus, uterine tubes, upper vagina, malformed testes

6. 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.

7. Trisomy 21 – Down’s syndrome High incidence in elderly pregnant primi mothers. Features- mentally retarded congenital heart defects simian creases in the hands

8. Trisomy 17-18 Features – M.R, congenital heart defects,low-set ear. Trisomy 13-15 M.R, congenital heart defects, deafness, cleft lip and palate, eye defects

9. Klinefelter’s syndrome XXY type- 47 chromosomes found in males. Features- sterility, testicular atrophy, gynecomastia.

10. Turner's syndrome XO-45 chromosomes, found in females. Absence of ovaries (Gonadal dysgenesis). Webbed neck, skeletal deformities, M.R.

11. 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 5 th chromosome). Features- microcephaly, micrognatha, M.R. and high pitched cat like cry or voice.