1. Inherited Metabolic Disorders

2. Inherited Metabolic Disorders
Humans have more that 6000 physiological diseases attributed to mutations in single genes and over 100 syndromes known to be caused by chromosomal abnormality.
The number of genetic disorders identified increases every year.

3. Sickle Cell Anaemia
This is most common in people of African, Mediterranean, Middle Eastern and Indian descent.
Autosomal mutation which results in the substitution of a single nucleotide in the HBB gene that codes for the beta Hb chain.
The allele is codominant.

4. Sickle Cell Anaemia Found on chromosome 11. Symptoms include:
Anaemia; mild to severe pain in the chest, joints, back or abdomen; jaundice; kidney failure; repeated infections; in particular pneumonia or meningitis; eye problems including blindness; swollen hands and feet; gall stones (at an early age); strokes

5. Sickle Cell Anaemia Patients are treated with folic acid.
acute episodes may require oxygen therapy, intravenous infusions of fluid and antibiotic drugs.
Experimental therapies include bone marrow transplants and gene therapy.

6. β-Thalassaemia Also known as Cooley Anaemia or Mediterranean Anaemia.
More common in people of Mediterranean and Middle Eastern descent.
Autosomal recessive mutation of the HBB gene coding for the haemoglobin beta chain.
It may arise through a gene deletion or a nucleotide deletion or insertion.

7. β-Thalassaemia Found on chromosome 11. Symptoms include:
The result of Hb with few or no Beta chains, causes severe anaemia during the first few years of life. People with this condition are tired and pale because not enough oxygen reaches the cells.

8. β-Thalassaemia Patients require frequent blood transfusions.
This causes iron build up in the organs, which is treated with drugs.
Bone marrow transplants and gene therapy hold promise and are probable future treatments.

9. Cystic Fibrosis Also known as Mucoviscidosis
Occurs 1 in every births in NZ, mostly amongst caucasians.
In NZ about 350 people have CF.
Autosomal recessive condition.
Over 500 mutations of the CFTR gene have been identified.
Found on chromosome 7.

10. Cystic Fibrosis
The CF gene’s protein product CFTR, is a membrane-based protein with a function in regulating the transport of Cl ions across the membrane.
The faulty gene leads to defective chloride transport.
This results in a net increase in water absorption by the cell.

11. Cystic Fibrosis
This accounts for the symptoms where mucus-secreting glands become fibrous and produce abnormally thick mucus.

12. Cystic Fibrosis Symptoms include:
Disruption of glands: the pancreas, intestinal glands, billiary tree, bronchial glands (chronic lung infections), and sweat glands (salt content depleted in hot environments). Infertility occurs in both males and females.

13. Cystic Fibrosis
Conventional treatment involves chest physiotherapy, a modified diet and the use of TOBI antibiotic to control lung infections.
Outlook: gene transfer therapy inserting normal CFTR gene using adenovirus vectors and liposomes.

14. Huntington Disease Also known as Huntington’s Chorea or HD.
An uncommon disease. (currently an estimated 1 in people in NZ have HD.)
An autosomal dominant mutation of the HD gene (IT15) caused by an increase in the length of a CAG repeat region ( times, normal range is repeats.)

15. Huntington Disease Found on Chromosome 4. Symptoms include:
Mutant gene forms defective protein huntingtin. Progressive, selective nerve cell death associated with chorea (jerky involuntary movements), psychiatric disorders and dementia (memory loss, disorientation, impaired ability to reason, and personality changes.)

16. Huntington Disease Surgical treatment may be possible.
Research is underway to find drugs that interfere with huntingtin protein.
Genetic counselling coupled with genetic screening of embryos may be developed in the future.