PMC4423033_01
Family pedigree.
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fig1
Family pedigree is shown in Figure 1.
Proband (on the right hand side of the photo) and his affected brother (on the left hand side of the photo) showing distorted facies and strong body build (a); lateral view of the face of the proband showing proptosis and prognathism (b); both hands of the proband showing bilateral radial deviation of index fingers, camptodactyly of 5th fingers, and soft tissue syndactyly between fingers (c); both feet of the proband showing bilateral broad big toes with wide space between the 1st and 2nd toes, bilateral clinodactyly of 4th and 5th toes, and hypoplastic nails and soft tissue syndactyly between toes (d).
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He had long face, broad forehead, depressed nasal root, midface hypoplasia, short philtrum, and macrognathia (Figure 2(a)). Broad chest with medial prominence of clavicles and long neck were other features (Figure 2(a)).
Radiological manifestations in patient 1. Skull X-ray (AP and lateral views) showing diffusely thickened dense calvarial bones of skull base and prognathism (a); X-ray chest (AP view) showing right clavicle and humerus and X-ray pelvis and upper part of both femora (AP view) with diffuse sclerotic texture and widened clavicles and ribs (b); X-ray of both hands (AP view) showing sclerotic appearance with medullary expansion of metacarpals and phalanges and hypoplastic terminal phalanges (c); X-ray of both feet (AP view) showing sclerotic appearance with medullary expansion of metatarsals and phalanges and hypoplastic terminal phalanges, bilateral hallux valgus, and overcrowded tarsal bones (d).
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X-ray studies showed diffuse thick dense cranial bones, thick calvarium, narrow skull base foramina, normal size and shape of sella turcica, hypoplastic maxilla, protruded mandible, diffuse sclerotic texture of long bones with medullary cavity expansion of metacarpals, and metatarsals and phalanges of hands and feet (Figure 3).
PMC4423033_02
Proband (on the right hand side of the photo) and his affected brother (on the left hand side of the photo) showing distorted facies and strong body build (a); lateral view of the face of the proband showing proptosis and prognathism (b); both hands of the proband showing bilateral radial deviation of index fingers, camptodactyly of 5th fingers, and soft tissue syndactyly between fingers (c); both feet of the proband showing bilateral broad big toes with wide space between the 1st and 2nd toes, bilateral clinodactyly of 4th and 5th toes, and hypoplastic nails and soft tissue syndactyly between toes (d).
BMRI2015-517815.002.jpg
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fig2
He had long face, broad forehead, depressed nasal root, midface hypoplasia, short philtrum, and macrognathia (Figure 2(a)). Broad chest with medial prominence of clavicles and long neck were other features (Figure 2(a)).
Paternal partial sequence chromatogram displaying the DNA sequence of affected proband, brother, and father (the mother showed the same father sequence chromatogram). The lined nucleotide indicates the position of the homozygous one nucleotide insertion (c.87_88insC, NCBI_rs377648601) resulting in a frameshift mutation and early stop codon. (*) and red box indicate the position of TGA stop codon. (/) indicates the substituent nucleotides. wt: wild type; Mt: mutant type; and aa: amino acids.
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This nucleotide change was confirmed in his parents in the heterozygous state (Figure 4).
Sclerostin model for wild type (a) and mutant sclerostin protein (b) where sclerostin protein was truncated at Asparagine (ASP) amino acid at codon 32 to present premature stop codon (PTC) D32X resulting in the discovered c.87_88insC mutation.
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fig5
To explore the truncated protein resulting in this mutation, we used SWISS-MODEL tool and UniProt database, where it was found that this mutation led to the production of 8-oligopeptide chain only after removing the first 23 signal peptide amino acids; besides that the resulting truncated protein did not contain C-terminal cysteine knot-like (CTCK) domain (Figures 5 and 6).
Sclerostin protein sequence illustrates the first 23 putative secretory signal sequences highlighted in green and CTCK domain highlighted in yellow. Altered amino acids are shadowed with gray highlighted substituents, and red star (*) indicated to end of the truncated sclerostin protein.
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fig6
To explore the truncated protein resulting in this mutation, we used SWISS-MODEL tool and UniProt database, where it was found that this mutation led to the production of 8-oligopeptide chain only after removing the first 23 signal peptide amino acids; besides that the resulting truncated protein did not contain C-terminal cysteine knot-like (CTCK) domain (Figures 5 and 6). D32X (Figure 6). Depending on bioinformatics prediction tools which were used in this study, we predicted that this mutation led to shortened truncated sclerostin (8 oligopeptides only) and created PTC at a 32 residue.