title: Pseudodominant inheritance of spondylocostal dysostosis type 1 caused by two familial delta-like 3 mutations.
abstract: Spondylocostal dysostoses (SCD) are a heterogeneous group of disorders of axial skeletal malformation characterized by multiple vertebral segmentation defects and rib anomalies. Sporadic cases with diverse phenotypes, sometimes including multiple organ abnormalities, are relatively common, and monogenic forms demonstrating autosomal recessive (AR) and, more rarely, autosomal dominant (AD) inheritance have been reported. We previously showed that mutations in delta-like 3 (DLL3), a somitogenesis gene that encodes a ligand for the notch signaling pathway, cause AR SCD with a consistent pattern of abnormal segmentation. We studied an SCD family previously reported to show AD inheritance, in which the phenotype is similar to that in AR cases. Direct DLL3 sequencing of individuals in two generations identified the affected father as homozygous for a novel frameshift mutation, 1440delG. His two affected children were compound heterozygotes for this mutation and a novel missense mutation, G504D, the first putative missense mutation reported in the transmembrane domain of DLL3. Their two unaffected siblings were heterozygotes for the 1440delG mutation. Pseudodominant inheritance has been confirmed, and the findings raise potential consequences for genetic counseling in relation to the SCD disorders.
authors.affiliation: Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, UK.
authors.forename: N V
authors.initials: NV
authors.lastname: Whittock
authors.forename: S
authors.initials: S
authors.lastname: Ellard
authors.forename: J
authors.initials: J
authors.lastname: Duncan
authors.forename: C E M
authors.initials: CE
authors.lastname: de Die-Smulders
authors.forename: J S H
authors.initials: JS
authors.lastname: Vles
authors.forename: P D
authors.initials: PD
authors.lastname: Turnpenny
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004252:DNA Mutational Analysis; D004413:Dysostoses / Q000175:diagnosis* / Q000235:genetics*; D004815:Epidermal Growth Factor / Q000235:genetics; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D020125:Mutation, Missense; D010375:Pedigree; D017434:Protein Structure, Tertiary / Q000235:genetics; D011859:Radiography; D017384:Sequence Deletion; D035781:Siblings; D013577:Syndrome; D013904:Thoracic Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging
chemical_list: C496666:DLL3 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D004815:Epidermal Growth Factor