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Limb body wall complex, amniotic band sequence, or new syndrome caused by mutation in IQ Motif containing K (IQCK)?

Kruszka P, Uwineza A, Mutesa L, Martinez AF, Abe Y, Zackai EH, Ganetzky R, Chung B, Stevenson RE, Adelstein RS, Ma X, Mullikin JC, Hong SK, Muenke M - Mol Genet Genomic Med (2015)

Bottom Line: Using whole exome sequencing, a de novo heterozygous mutation was found in the gene IQCK: c.667C>G; p.Q223E and confirmed by Sanger sequencing in an individual with LBWC.Human wild-type IQCK mRNA rescued the zebrafish phenotype, whereas human p.Q223E IQCK mRNA did not, but worsened the phenotype of the morpholino knockdown zebrafish.This study supports a genetic etiology for LBWC/ABS, or potentially a new syndrome.

View Article: PubMed Central - PubMed

Affiliation: Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health Bethesda, Maryland.

ABSTRACT
Limb body wall complex (LBWC) and amniotic band sequence (ABS) are multiple congenital anomaly conditions with craniofacial, limb, and ventral wall defects. LBWC and ABS are considered separate entities by some, and a continuum of severity of the same condition by others. The etiology of LBWC/ABS remains unknown and multiple hypotheses have been proposed. One individual with features of LBWC and his unaffected parents were whole exome sequenced and Sanger sequenced as confirmation of the mutation. Functional studies were conducted using morpholino knockdown studies followed by human mRNA rescue experiments. Using whole exome sequencing, a de novo heterozygous mutation was found in the gene IQCK: c.667C>G; p.Q223E and confirmed by Sanger sequencing in an individual with LBWC. Morpholino knockdown of iqck mRNA in the zebrafish showed ventral defects including failure of ventral fin to develop and cardiac edema. Human wild-type IQCK mRNA rescued the zebrafish phenotype, whereas human p.Q223E IQCK mRNA did not, but worsened the phenotype of the morpholino knockdown zebrafish. This study supports a genetic etiology for LBWC/ABS, or potentially a new syndrome.

No MeSH data available.


Related in: MedlinePlus

Box shows location of missense mutation in IQCK; (A) control morpholino phenotype at 48 h in zebrafish is normal; (B) iqck morpholino at 48 h shows cardiac edema (red arrow) and ventral fin hypoplasia (yellow arrow); (C) coinjection of iqck morpholino and IQCK (hIQCK) mRNA shows rescued phenotype; (D) control human IQCK injection results in normal phenotype; (E) coinjection of iqck morpholino and human Q223E human IQCK mRNA resulting in worsening of phenotype than iqck morpholino alone shown in Figure6B; (F) human Q223E IQCK mRNA injection shows normal phenotype; (G) coinjection of iqck morpholino and human Q223H human IQCK mRNA resulting failure to rescue phenotype; (H) human Q223H IQCK mRNA injection shows normal phenotype; (I) coinjection of iqck morpholino and human Q222S human IQCK mRNA resulting in a rescued phenotype; (J) human Q222S IQCK mRNA injection shows normal phenotype.
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fig06: Box shows location of missense mutation in IQCK; (A) control morpholino phenotype at 48 h in zebrafish is normal; (B) iqck morpholino at 48 h shows cardiac edema (red arrow) and ventral fin hypoplasia (yellow arrow); (C) coinjection of iqck morpholino and IQCK (hIQCK) mRNA shows rescued phenotype; (D) control human IQCK injection results in normal phenotype; (E) coinjection of iqck morpholino and human Q223E human IQCK mRNA resulting in worsening of phenotype than iqck morpholino alone shown in Figure6B; (F) human Q223E IQCK mRNA injection shows normal phenotype; (G) coinjection of iqck morpholino and human Q223H human IQCK mRNA resulting failure to rescue phenotype; (H) human Q223H IQCK mRNA injection shows normal phenotype; (I) coinjection of iqck morpholino and human Q222S human IQCK mRNA resulting in a rescued phenotype; (J) human Q222S IQCK mRNA injection shows normal phenotype.

Mentions: Functional studies using MO knockdown showed a significant phenotype in the zebrafish embryo at 48 h past fertilization (hpf). While the control MO showed a normal phenotype (Fig.6A), the iqck morpholino showed cardiac edema and poor development of the ventral fin (Fig.6B). Coinjection of human IQCK wild-type mRNA rescued the iqck MO phenotype (Fig.5C) with reduction in heart edema and normal growth of ventral part of fin, (Fig.6C), whereas human p.Q223E mRNA worsened this phenotype (Fig.6E) with markedly decreased tail development and increased cardiac edema. However, when the human p.Q223E mRNA was administered without the iqck MO, the zebrafish phenotype was unaffected (Fig.6F). When rescue of the iqck MO was attempted using histidine (H) versus glutamic acid (E) with p.Q223H human mRNA, the phenotype remained unchanged (not rescued) (Fig.6G). Coinjection of p.I222S human mRNA (also a conserved amino acid in the IQ domain) only partially rescued the MO phenotype (Fig.6I). These results suggest that the conserved glutamine in position 223 is essential and that the p.Q223E mutation is pathogenic.


Limb body wall complex, amniotic band sequence, or new syndrome caused by mutation in IQ Motif containing K (IQCK)?

Kruszka P, Uwineza A, Mutesa L, Martinez AF, Abe Y, Zackai EH, Ganetzky R, Chung B, Stevenson RE, Adelstein RS, Ma X, Mullikin JC, Hong SK, Muenke M - Mol Genet Genomic Med (2015)

Box shows location of missense mutation in IQCK; (A) control morpholino phenotype at 48 h in zebrafish is normal; (B) iqck morpholino at 48 h shows cardiac edema (red arrow) and ventral fin hypoplasia (yellow arrow); (C) coinjection of iqck morpholino and IQCK (hIQCK) mRNA shows rescued phenotype; (D) control human IQCK injection results in normal phenotype; (E) coinjection of iqck morpholino and human Q223E human IQCK mRNA resulting in worsening of phenotype than iqck morpholino alone shown in Figure6B; (F) human Q223E IQCK mRNA injection shows normal phenotype; (G) coinjection of iqck morpholino and human Q223H human IQCK mRNA resulting failure to rescue phenotype; (H) human Q223H IQCK mRNA injection shows normal phenotype; (I) coinjection of iqck morpholino and human Q222S human IQCK mRNA resulting in a rescued phenotype; (J) human Q222S IQCK mRNA injection shows normal phenotype.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585450&req=5

fig06: Box shows location of missense mutation in IQCK; (A) control morpholino phenotype at 48 h in zebrafish is normal; (B) iqck morpholino at 48 h shows cardiac edema (red arrow) and ventral fin hypoplasia (yellow arrow); (C) coinjection of iqck morpholino and IQCK (hIQCK) mRNA shows rescued phenotype; (D) control human IQCK injection results in normal phenotype; (E) coinjection of iqck morpholino and human Q223E human IQCK mRNA resulting in worsening of phenotype than iqck morpholino alone shown in Figure6B; (F) human Q223E IQCK mRNA injection shows normal phenotype; (G) coinjection of iqck morpholino and human Q223H human IQCK mRNA resulting failure to rescue phenotype; (H) human Q223H IQCK mRNA injection shows normal phenotype; (I) coinjection of iqck morpholino and human Q222S human IQCK mRNA resulting in a rescued phenotype; (J) human Q222S IQCK mRNA injection shows normal phenotype.
Mentions: Functional studies using MO knockdown showed a significant phenotype in the zebrafish embryo at 48 h past fertilization (hpf). While the control MO showed a normal phenotype (Fig.6A), the iqck morpholino showed cardiac edema and poor development of the ventral fin (Fig.6B). Coinjection of human IQCK wild-type mRNA rescued the iqck MO phenotype (Fig.5C) with reduction in heart edema and normal growth of ventral part of fin, (Fig.6C), whereas human p.Q223E mRNA worsened this phenotype (Fig.6E) with markedly decreased tail development and increased cardiac edema. However, when the human p.Q223E mRNA was administered without the iqck MO, the zebrafish phenotype was unaffected (Fig.6F). When rescue of the iqck MO was attempted using histidine (H) versus glutamic acid (E) with p.Q223H human mRNA, the phenotype remained unchanged (not rescued) (Fig.6G). Coinjection of p.I222S human mRNA (also a conserved amino acid in the IQ domain) only partially rescued the MO phenotype (Fig.6I). These results suggest that the conserved glutamine in position 223 is essential and that the p.Q223E mutation is pathogenic.

Bottom Line: Using whole exome sequencing, a de novo heterozygous mutation was found in the gene IQCK: c.667C>G; p.Q223E and confirmed by Sanger sequencing in an individual with LBWC.Human wild-type IQCK mRNA rescued the zebrafish phenotype, whereas human p.Q223E IQCK mRNA did not, but worsened the phenotype of the morpholino knockdown zebrafish.This study supports a genetic etiology for LBWC/ABS, or potentially a new syndrome.

View Article: PubMed Central - PubMed

Affiliation: Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health Bethesda, Maryland.

ABSTRACT
Limb body wall complex (LBWC) and amniotic band sequence (ABS) are multiple congenital anomaly conditions with craniofacial, limb, and ventral wall defects. LBWC and ABS are considered separate entities by some, and a continuum of severity of the same condition by others. The etiology of LBWC/ABS remains unknown and multiple hypotheses have been proposed. One individual with features of LBWC and his unaffected parents were whole exome sequenced and Sanger sequenced as confirmation of the mutation. Functional studies were conducted using morpholino knockdown studies followed by human mRNA rescue experiments. Using whole exome sequencing, a de novo heterozygous mutation was found in the gene IQCK: c.667C>G; p.Q223E and confirmed by Sanger sequencing in an individual with LBWC. Morpholino knockdown of iqck mRNA in the zebrafish showed ventral defects including failure of ventral fin to develop and cardiac edema. Human wild-type IQCK mRNA rescued the zebrafish phenotype, whereas human p.Q223E IQCK mRNA did not, but worsened the phenotype of the morpholino knockdown zebrafish. This study supports a genetic etiology for LBWC/ABS, or potentially a new syndrome.

No MeSH data available.


Related in: MedlinePlus