Scientific background:

Summary: Mutations of this gene cause juvenile-onset primary open angle glaucoma.

Gene: The gene MYOC, formerly named GLC1A, is about 17kb in size. It consists of 3 large exons. It is located on chromosome 1 (1q24.3-q25.2).

Pathology: The protein product of that gene is the trabecular meshwork-induced glucocorticoid response protein (TIGR). It was assumed that a mutation of this gene causes disturbances of ocular water efflux. But more recent investigations showed its function ocular muscles.

Clinical signs: The clinical picture is the juvenile open angle glaucoma.

Epidemiology: The mutation is mostly described in Caucasians. In about 4% of patients with primary open angle glaucoma this mutation is present.

Interpretation: The importance of this investigation is in family consulting and early diagnosis of family members.

Test strategy: Patients with primary open angle glaucoma and family history. Other members of an affected family.

Methodology:

	clinical test	Method		Genomic sequencing of the entire coding region
		Turn-around time		25 working days
		Effort		medium
		Specimen		DNA
		Quality assessment		Internal quality control only
	All known and new missense, nonsense and splice mutations can be detected.
	clinical test	Method		Carrier testing
		Turn-around time		5 working days
		Effort		little
		Specimen		DNA
		Quality assessment		Internal quality control only
	The test is only specific about the mutation already known in this kindred.

Literature: 

Alward WL et al. (1998) Clinical features associated with mutations in the chromosome 1 open-angle glaucoma gene (GLC1A)
Kanagavalli J et al. (2004) A review of genetic and structural understanding of the role of myocilin in primary open angle glaucoma.