LIST OF COMMUNICABLE DISEASES

          Genetic disorders can occur either due to change in chromosome number or structure or mutations. Some of these genetic disorders are listed below.

Name of the disorder	Cause	Symptoms
I On the basis change in chromosome structure
1.Cri-du-chat syndrome	Deletion of whole or part of the short arm of chromosome 5	Infant’s cry like the mewing of a cat, moon like face.
II. On the basis change in chromosome number
1.Down’s syndrome (Mongolism)	Trisomy of chromosome 21	Mentally and physically retarded, round face with broad skull
2.Edward’s syndrome	Trisomy of chromosome 18	Mental retardation with several congenital malformations
3.Klinefilter’s Syndrome	Additional X-chromosome (XO)	Phenotypically females with rudimentary sex organs and mammary glands
4.Turner’s syndrome	Lake of X-chromosome 13	Cleft lip, deafness, mental retardation
5.Patau Syndrome	Trisomy of chromosome 13	Cleft lip, deafness, mental retardation
III. Gene mutation
1.Albinism	Recessive gene which blocks conversion of amino acid tyrosine to melanin	Lack of pigment in the skin, hair and iris of the eyes
2.Cystic fibrosis	Recessive autosomal gene in homozygous condition	Increased susceptibility of lung infection, abnormal pancreatic function
3.Fabry’s disease	Recessive X-linked (sex-linked) gene which blocks metabolism of glycophingolipids	Lipids as crystals deposit on the walls of blood vessels of heart, kidneys, eyes, causing shooting pain
4. Hemophilia	Sex-linked recessive gene causing defective synthesis of clotting factor	Haemorrhage
5.Huntington’s disease	Dominant autosomal gene	Develops at the late age of 30-40 years and slowly leads to loss of control on the movement of limbs
6.Muscular dystrophy (Duchenne type)	Sex-linked recessive gene during childhood  recessive gene causing defective synthesis of clotting factor	Haemorrhage
7.Phenylketonuria (PKU)	Recessive autosomal gene in homozygous condition	Brain damage leading to mental retardation
8.Sickle cell anaemia	Recessive autosomal gene in homozygous condition resulting in abnormal haemoglobin	Inability to carry oxygen by blood
9. Tay-sachs disease	Recessive autosomal gene after 8-9 months	Degeneration of cerebral function leading to epilepsy, paralysis or even blindness
10. Thalassemia (Cooley’s anaemia)	Recessive gene in homozygous condition	Severe anaemia
11. Leasch-Nyhan syndrome	Sex-linked (x-linked)recessive trait	Development of involuntary movements, mental retardation
12Marfan’s Syndrome	Autosomal dominant	Abnormalities of the eyes, cardiovascular and skeletal system