|TAT (TURNAROUND TIME)||2 - 4 weeks|
|CPT CODE||81302, 81304, 81407, 81479|
|RECOMMENDED MNG KITS||
Microcephaly is defined as a small cranium with an occipito-frontal head circumference (OFC) of more than two standard deviations (SD) below the mean for age, sex, and ethnicity. Microcephaly can be congenital (primary microcephaly) or develop postnatally (secondary microcephaly). Either type can be caused by environmental or genetic factors.
Individuals with primary microcephaly have inadequate brain growth during pregnancy, and are born with a significantly small head size (OFC of < 3 SD). They may also develop mild to severe intellectual disabilities, seizures, mild short stature, and a narrow sloping forehead due to the reduced cranial size.
Imaging typically reveals a normal brain structure with reduction in size, particularly of the cerebral cortex. The brain size in cases of secondary microcephaly has the expected brain size at birth but subsequently fails to grow normally. Secondary microcephaly is observed in some metabolic disorders or genetic syndromes, such as Rett or Angelman syndromes, in which a progressive reduction in head circumference is seen in infancy or early childhood.
Congenital and postnatal microcephaly can present as an isolated finding in an individual, be associated with other brain malformations such as cerebellar hypoplasia, or be part of an underlying syndrome. Syndromic microcephaly can be caused by chromosomal abnormalities, inborn errors of metabolism, single gene disorders, trauma and infection. The inheritance patterns can be autosomal dominant, autosomal recessive or x-linked.
|Acceptable Sample Types||
|Sample Preparation:||Acceptable specimen types: (1) Blood specimens: Draw blood in an EDTA tube. Preferred volume: 4 milliliters (adults and pediatrics), Minimum volume: 2 milliliters; (2) DNA extracted from leukocytes, muscle, or fibroblasts: Preferred quantity: 4 micrograms, Minimum quantity: 3 micrograms (Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0.); (3) 2 T-25 flasks of fibroblasts; (4) 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80°Celsius or below. (5) Skin biopsy (Fibroblasts will be cultured from skin specimen for genetic testing): Skin biopsy may be taken from the inner forearm with a sterile skin punch (2-5 millimeters) or at incision site of muscle biopsy. Site is sterilized with alcohol swabs only (other reagents will inhibit cell isolation/growth). Biopsy site may be anaesthetized with 2% lidocaine with epinephrine. Depth of punch is 2mm. Transfer skin biopsy into 15 milliliter conical tube filled with sterile culture media. Cell culture media may be requested from MNG; (6) Buccal cells.|
|Shipping Condition:||Shipping instructions: MNG Kits are available for free shipping of specimens. Please see our website for details. If you are not using a MNG Kit: (1) Blood specimens should be shipped in a secure container at room temperature. (2) Extracted DNA should be shipped frozen in an insulated container with 5-7lbs dry ice. (3) T-25 flasks containing fibroblasts should be shipped in an insulated container at room temperature. Flasks should be completely filled with media and cells should be ~90% confluent. Fibroblast samples must be certified free from Mycoplasma. MNG is able to perform this service for a small charge. (4) Muscle samples should be shipped frozen in an insulated container with 5-7 lbs dry ice. All samples should be shipped overnight at the proper temperature for receipt by our lab Monday thru Saturday (No Sunday or holiday deliveries accepted). (5) Skin Biopsy: Conical containing the skin specimen should be shipped in a secure container with cold pack (DO NOT FREEZE). Ship priority overnight.|