Microcephaly


Test Details
TEST CODE NGS425
TEST METHODOLOGY NGS
TAT (TURNAROUND TIME) 2 - 4 weeks
GENES 296
CPT CODE 81302, 81304, 81407, 81479
PRICE $1795
RECOMMENDED MNG KITS
  • SINGLE Blood Genetic Testing
  • Buccal Swab Genetic Testing

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Clinical Information
Clinical Significance

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.

Relevant Diseases
  • Microcephaly

Specimen Information
Acceptable Sample Types
  • Muscle
  • Cultured Fibroblasts
  • Whole Blood - EDTA
  • Extracted DNA - Leukocytes
  • Buccal Cells
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.

Genes Assessed
AAAS
AARS
ACADSB
ACE
ACO2
ACSL4
ACTB
ADAR
ADD3
AGA
AIMP1
ALDH18A1
ALG1
ALG3
ALG9
AMPD2
AP3B1
AP3B2
AP3D1
AP4B1
AP4E1
AP4M1
AP4S1
ARCN1
ARFGEF2
ARSE
ARX
ASNS
ASPM
ATP5A1
ATP6V0A2
ATP7A
ATPAF2
ATRX
AUTS2
BCL11A
BCOR
BRPF1
CARS2
CASC5
CASK
CCDC88A
CDC45
CDC6
CDK5RAP2
CDKL5
CDT1
CENPJ
CEP135
CEP152
CEP290
CHD7
CHKB
CHMP1A
CIT
CLP1
CLPP
COG6
COQ9
COX15
COX7B
CPT2
CREBBP
CTNNB1
CTSD
DCPS
DGUOK
DHCR24
DHCR7
DHFR
DHTKD1
DKC1
DLAT
DLD
DNA2
DNM1L
DOLK
DPAGT1
DPM1
DPM2
DYM
DYNC1H1
DYRK1A
EDC3
EHMT1
ELOVL4
ERCC1
ERCC2
ERCC4
ERCC5
ERCC6
ERCC8
EXOSC3
FAM20C
FANCA
FARS2
FBLN5
FIG4
FKRP
FOXG1
GAD1
GBA
GFM1
GJA1
GLI2
GMPPB
GNPAT
GPT2
HCCS
HCFC1
HMGB3
HNRNPH2
HSPD1
IARS
IBA57
IER3IP1
IFIH1
IFT74
IGF1R
IQSEC2
ITPA
KCNJ2
KCNT1
KDM5C
KIAA2022
KIF1A
KIF2A
KMT2D
L1CAM
LARP7
LIAS
LINS
MBD5
MBOAT7
MBTPS2
MCOLN1
MCPH1
MECP2
MED25
MFSD2A
MGAT2
MICU1
MKS1
MOCS1
MOCS2
MPC1
MPLKIP
MRPS22
MTFMT
MTHFR
MVK
MYH3
NAA10
NANS
NIPBL
NKAIN2
NSD2
NSDHL
NSMCE2
NSUN2
OCLN
OFD1
ORC1
ORC4
ORC6
PAFAH1B1
PAH
PAK3
PALB2
PARN
PDHA1
PDHX
PEX5
PEX7
PGAP2
PGAP3
PHF6
PHGDH
PIEZO2
PIGA
PIGO
PIGY
PLEKHG2
PLP1
PMM2
PNKP
PNPO
POMGNT1
POMK
POMT1
POMT2
PORCN
PPT1
PQBP1
PRMT7
PSPH
PTDSS1
PTS
PUS1
PUS3
PYCR1
QDPR
RAD21
RARS
RARS2
RELN
RFT1
RLIM
RNASEH2A
RNASEH2B
RNASEH2C
RNU4ATAC
RPL10
RPS19
RPS6KA3
RTTN
SAMHD1
SASS6
SATB2
SBF1
SCN1A
SCN8A
SCN9A
SEMA3E
SEPSECS
SERAC1
SHH
SIL1
SIX3
SKI
SLC13A5
SLC16A2
SLC1A2
SLC1A4
SLC25A1
SLC25A19
SLC25A22
SLC2A1
SLC35A2
SLC35C1
SLC39A14
SLC6A8
SLC6A9
SLC9A6
SLX4
SMAD4
SMARCA2
SMARCA4
SMARCB1
SMARCE1
SMC1A
SMC3
SNAP29
SNRPB
SPR
SPTAN1
SSR4
ST3GAL5
STIL
STT3B
SYNGAP1
TAF1
TBC1D20
TBC1D24
TBL1XR1
TBX1
TCF4
TCTN2
TELO2
TMEM165
TMTC3
TRAPPC9
TREX1
TRMT10A
TSEN2
TSEN34
TSEN54
TUBB2B
TUBB3
TUBB4A
TUBG1
UBE3A
VARS2
VIPAS39
VPS33B
VPS53
WDR62
WWOX
XPA
ZBTB18
ZC4H2
ZEB2
ZIC1
ZNF148
ZNF335
ZNF592

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