Microcephaly


Test Details
TEST CODE NGS425
TEST METHODOLOGY NGS
TAT (TURNAROUND TIME) 2 - 4 weeks
GENES 494
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
ACD
ACE
ACO2
ACSL4
ACTB
ADAR
ADAT3
ADD3
AGA
AGT
AGTR1
AIMP1
ALDH18A1
ALG1
ALG3
ALG9
AMPD2
ANKLE2
ANKRD11
AP3B1
AP3B2
AP3D1
AP4B1
AP4E1
AP4M1
AP4S1
ARCN1
ARFGEF2
ARHGAP31
ARSE
ARX
ASNS
ASPM
ASXL1
ATP5A1
ATP6V0A2
ATP7A
ATPAF2
ATR
ATRX
AUTS2
B3GALTL
BCAP31
BCL11A
BCOR
BMP4
BRAT1
BRCA2
BRF1
BRPF1
BUB1B
C2CD3
CARS2
CASC5
CASK
CCDC88A
CD96
CDC45
CDC6
CDK13
CDK5RAP2
CDK6
CDKL5
CDT1
CENPE
CENPF
CENPJ
CEP135
CEP152
CEP290
CEP57
CEP63
CHAMP1
CHD7
CHKB
CHMP1A
CIT
CKAP2L
CLP1
CLPB
CLPP
CNNM2
COG2
COG6
COL4A2
COL4A3BP
COQ9
COX15
COX7B
CPT2
CREBBP
CRIPT
CSNK2A1
CTCF
CTNNB1
CTSD
CYB5R3
DCPS
DDX11
DDX3X
DGUOK
DHCR24
DHCR7
DHFR
DHTKD1
DIAPH1
DKC1
DLAT
DLD
DNA2
DNM1L
DOCK6
DOLK
DONSON
DPAGT1
DPM1
DPM2
DYM
DYNC1H1
DYRK1A
EBF3
EDC3
EFTUD2
EHMT1
EIF2AK3
ELAC2
ELOVL4
EMC1
EMG1
ENTPD1
EP300
EPG5
ERCC1
ERCC2
ERCC4
ERCC5
ERCC6
ERCC6L2
ERCC8
ESCO2
EXOSC3
FAM20C
FANCA
FANCC
FANCD2
FANCE
FANCI
FAR1
FARS2
FBLN5
FGFR1
FGFR3
FIG4
FKRP
FOXG1
FRAS1
FREM1
FREM2
FRMD4A
FTO
GAD1
GBA
GFM1
GJA1
GLI2
GLYCTK
GMNN
GMPPB
GNPAT
GORAB
GPT2
GPX4
GRIP1
GTF2E2
HAAO
HACE1
HCCS
HCFC1
HIVEP2
HMGB3
HNRNPH2
HSPD1
HYLS1
IARS
IBA57
IER3IP1
IFIH1
IFT140
IFT74
IGF1
IGF1R
IKBKG
IQSEC2
ITGA3
ITPA
JAM3
KAT6A
KAT6B
KATNB1
KCNJ2
KCNJ6
KCNT1
KDM5C
KIAA0586
KIAA1279
KIAA2022
KIF11
KIF14
KIF1A
KIF2A
KIF5C
KMT2C
KMT2D
KYNU
L1CAM
LAGE3
LARP7
LARS
LIAS
LIG4
LINS
LIPT2
LRP5
MAPRE2
MASP1
MBD5
MBOAT7
MBTPS2
MCM4
MCOLN1
MCPH1
MECP2
MED17
MED25
MFF
MFSD2A
MGAT2
MICU1
MIR17HG
MKS1
MOCS1
MOCS2
MPC1
MPLKIP
MRPS22
MRPS34
MSMO1
MTFMT
MTHFR
MVK
MYCN
MYH3
MYO18B
NAA10
NACC1
NADK2
NALCN
NANS
NAT8L
NBN
NDE1
NIN
NIPBL
NKAIN2
NOP10
NSDHL
NSMCE2
NSUN2
NUS1
OCLN
OFD1
OGT
ORC1
ORC4
ORC6
OSGEP
PAFAH1B1
PAH
PAK3
PALB2
PARN
PCLO
PCNA
PCNT
PDHA1
PDHX
PEX5
PEX7
PGAP2
PGAP3
PGBD3
PHC1
PHF6
PHGDH
PIEZO2
PIGA
PIGO
PIGY
PLEKHG2
PLK4
PLP1
PMM2
PNKP
PNPO
POC1A
POGZ
POLR1A
POMGNT1
POMK
POMT1
POMT2
POR
PORCN
PPP1R15B
PPP2R1A
PPT1
PQBP1
PRKD1
PRKDC
PRMT7
PSAT1
PSPH
PTDSS1
PTF1A
PTRH2
PTS
PUF60
PUS1
PUS3
PYCR1
PYCR2
QARS
QDPR
RAB18
RAB3GAP1
RAB3GAP2
RAC1
RAD21
RAD51
RARS
RARS2
RBBP8
RBPJ
RELN
REN
RFT1
RLIM
RNASEH2A
RNASEH2B
RNASEH2C
RNASET2
RNF113A
RNF168
RNU4ATAC
ROBO3
RPL10
RPS19
RPS23
RPS6KA3
RSPRY1
RTEL1
RTTN
SALL1
SAMHD1
SASS6
SATB2
SBF1
SC5D
SCN1A
SCN8A
SCN9A
SEMA3E
SEPSECS
SERAC1
SF3B4
SGPL1
SHH
SIL1
SIN3A
SIX3
SKI
SLC13A5
SLC16A2
SLC1A2
SLC1A4
SLC25A1
SLC25A19
SLC25A22
SLC2A1
SLC35A2
SLC35A3
SLC35C1
SLC39A14
SLC6A8
SLC6A9
SLC9A6
SLX4
SMAD4
SMARCA2
SMARCA4
SMARCB1
SMARCE1
SMC1A
SMC3
SMG9
SNAP29
SNRPB
SOX11
SOX2
SP110
SPATA5
SPR
SPTAN1
SSR4
ST3GAL5
STAG1
STAMBP
STIL
STT3B
SYNGAP1
TAF1
TAF2
TAF6
TANGO2
TAPT1
TBC1D20
TBC1D24
TBCE
TBL1XR1
TBX1
TCF4
TCTN2
TECPR2
TELO2
TERT
TFAP2A
THOC2
THOC6
TINF2
TMCO1
TMEM165
TMTC3
TP53RK
TRAIP
TRAPPC11
TRAPPC9
TREX1
TRIO
TRMT10A
TSEN15
TSEN2
TSEN34
TSEN54
TTI2
TUBB2B
TUBB3
TUBB4A
TUBG1
TUBGCP4
TUBGCP6
TWIST1
TXN2
UBE3A
UBE3B
UBR1
UNC80
UPB1
VARS
VARS2
VIPAS39
VPS11
VPS33B
VPS53
WDFY3
WDR62
WDR73
WHSC1
WWOX
XPA
XRCC2
XRCC4
YME1L1
ZBTB16
ZBTB18
ZC4H2
ZEB2
ZIC1
ZNF148
ZNF335
ZNF592
ZNHIT3

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