Autosomal dominant traits

Criteria

• Affected children have at least one affected parent

• Dominant traits have a linear pattern (show up in every generation)

• Males and females can be affected

• Male-to-male transmission can occur

• Males and females can transmit the trait with equal frequency

• Transmission stops after a generation in which no one is affected

What is Huntington’s disease?

A progressive neurogenerative disorder

Huntington’s symptoms

• Jerky movements

• Memory deficits

• Loss of attention

• Slurred speech

• Mood swings

• Late onset

How common is Huntington’s?

8.2 to 9 per 100,000 people in North America and Europe

What gene causes Huntington’s?

HTT gene

HTT gene

• Important role in embryonic development

• Involved in vesicular transport, endocytosis, regulation of transcription

• It is expressed throughout the body

• Spans 180,000 nucleotides across chromosome 4

• 3142 amino acids

• 348 kDa in size

What is polydactyly?

Extra toes or fingers

How common is polydactyly?

1 in every 500 live births

What is achondroplasia (ACH)

The most frequent form of short-limb dwarfism

What gene causes ACH?

A mutation in the FGFR3 gene

FGFR3 function

• Maintenance of bone and brain tissue

• Mainly expressed in cartilage