Trismus-Pseudocamptodactyly Syndrome: MYH8 Sequencing

Alternate test name

Distal Arthrogryposis type 7; Hecht syndrome

Gene name / Alternate gene name

MYH8

Protein

Myosin heavy chain 8

Lab area

Genome Diagnostics - Molecular Genetics

Method and equipment

Sequencing

Expected turn-around time

Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks

Specimen type

Blood; gDNA.

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Specimen requirements

Blood: 5-10 mL in EDTA, 0.5 mL in EDTA (neonate);
DNA-minimum 10 ug in 100 uL low TE (pH8.0)

Storage and transportation

Room Temperature

For details about specimen requirements, please refer to: Specimen Type and Requirements

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Shipping information

The Hospital for Sick Children

Division of Genome Diagnostics

555 University Avenue, Black Wing, Room 3416

Toronto, ON

Canada

M5G 1X8

Phone: 416-813-7200 ext. 2

Hours: Monday to Friday, 8 a.m. to 4:30 p.m.

Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642

Email Molecular Lab: molecular.lab@sickkids.ca

Email Cytogenetics: cytogenetics.requests@sickkids.ca

Requisition

Trismus-Pseudocamptodactyly Syndrome: MYH8 Sequencing - requisition

Background and clinical significance

Patients with trismus-pseudocamptodactyly syndrome may show cardiac myxomas, spotty skin pigmentation alone or in combination with cutaneous lesions. Most affected individuals have distal arthrogryposis, including pseudocamptodactyly of the hands and feet, trismus, or both, which improves symptomatically with aging.

Trismus-pseudocamptodactyly syndrome is an autosomal dominant disorder caused by a deficiency of a perinatal skeletal myosin heavy chain. The syndrome is caused by mutations in the MYH8 gene which has been mapped to chromosome 17p13.1. A single mutation, p.Arg674Gln, has been described in several families of Belgian descent.

Trismus-pseudocamptodactyly syndrome is present when an individual has one copy of the defective gene. There is a 50% chance that baby will inherit the mutation for trismus-pseudocamptodactyly syndrome and thus may develop symptoms in the perinatal period. There is a 50% chance that the baby will not have trismus-pseudocamptodactyly syndrome.

See related information sheet: Trismus-pseudocamptodactyly syndrome

Disease condition

Trismus-Pseudocamptodactyly Syndrome