TBX15 mutations cause craniofacial dysmorphism, hypoplasia of scapula and pelvis, and short stature in Cousin syndrome.
Members of the evolutionarily conserved T-box family of transcription factors are important players in developmental processes that include mesoderm formation and patterning and organogenesis both in vertebrates and invertebrates. The importance of T-box genes for human development is illustrated by the association between mutations in several of the 17 human family members and congenital errors of morphogenesis that include cardiac, craniofacial, and limb malformations. We identified two unrelated individuals with a complex cranial, cervical, auricular, and skeletal malformation syndrome with scapular and pelvic hypoplasia (Cousin syndrome) that recapitulates the dysmorphic phenotype seen in the Tbx15-deficient mice, droopy ear. Both affected individuals were homozygous for genomic TBX15 mutations that resulted in truncation of the protein and addition of a stretch of missense amino acids. Although the mutant proteins had an intact T-box and were able to bind to their target DNA sequence in vitro, the missense amino acid sequence directed them to early degradation, and cellular levels were markedly reduced. We conclude that Cousin syndrome is caused by TBX15 insufficiency and is thus the human counterpart of the droopy ear mouse.
Lausch
Ekkehart
E
Centre for Pediatrics and Adolescent Medicine, Department of Pediatrics, University of Freiburg, 79106 Freiburg, Germany.
Hermanns
Pia
P
Farin
Henner F
HF
Alanay
Yasemin
Y
Unger
Sheila
S
Nikkel
Sarah
S
Steinwender
Christoph
C
Scherer
Gerd
G
Spranger
Jürgen
J
Zabel
Bernhard
B
Kispert
Andreas
A
Superti-Furga
Andrea
A
D001827:Body Height / Q000235:genetics*; D002648:Child; D019465:Craniofacial Abnormalities / Q000000981:diagnostic imaging / Q000235:genetics*; D005260:Female; D006801:Humans; D009154:Mutation; D020125:Mutation, Missense; D010388:Pelvis / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D012540:Scapula / Q000000981:diagnostic imaging / Q000473:pathology*; D013577:Syndrome; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
D020825:T-Box Domain Proteins; C523795:TBX15 protein, human