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The etiology of idiopathic short stature (ISS) and Leri-Weill dyschondrosteosis (LWD) in European patients is known to include SHOX mutations and copy-number variations (CNVs) involving SHOX and/or the highly evolutionarily conserved non-coding DNA elements (CNEs) flanking the gene. However, the frequency and types of SHOX abnormalities in non-European patients and the clinical importance of mutations in the CNEs remains to be clarified. Here, we performed systematic molecular analyses of SHOX for 328 Japanese patients with ISS or LWD. SHOX abnormalities accounted for 3.8% of ISS and 50% of LWD cases. CNVs around SHOX were identified in 16 cases, although the ~47 kb deletion frequently reported in European patients was absent in our cases. Probably damaging mutations and benign/silent substitutions were detected in four cases, respectively. Although CNE-linked substitutions were detected in 15 cases, most of them affected poorly conserved nucleotides and were shared by unaffected individuals. These results suggest that the frequency and mutation spectrum of SHOX abnormalities are comparable between Asian and European patients, with the exception of a European-specific downstream deletion. Furthermore, this study highlights the clinical importance and genetic heterogeneity of the SHOX-flanking CNVs, and indicates a limited clinical significance of point mutations in the CNEs.

Context: Mutations of multiple transcription factor genes involved in pituitary development have been identified in a minor portion of patients with combined pituitary hormone deficiency (CPHD). However, copy number aberrations involving such genes have been poorly investigated in patients with CPHD., Objective: We aimed to report the results of mutation and gene copy number analyses in patients with CPHD., Subjects and Methods: Seventy-one Japanese patients with CPHD were examined for mutations and gene copy number aberrations affecting POU1F1, PROP1, HESX1, LHX3, LHX4, and SOX3 by PCR-direct sequencing and multiplex ligation-dependent probe amplification. When a deletion was indicated, it was further studied by fluorescence in situ hybridization, oligoarray comparative genomic hybridization, and serial sequencing for long PCR products encompassing the deletion junction., Results: We identified a de novo heterozygous 522,009-bp deletion involving LHX4 in a patient with CPHD (GH, TSH, PRL, LH, and FSH deficiencies), anterior pituitary hypoplasia, ectopic posterior pituitary, and underdeveloped sella turcica. We also identified five novel heterozygous missense substitutions (p.V201I and p.H387P in LHX4, p.T63M and p.A322T in LHX3, and p.V53L in SOX3) that were assessed as rare variants by sequencing analyses for control subjects and available parents and by functional studies and in silico analyses., Conclusions: The results imply the rarity of abnormalities affecting the six genes in patients with CPHD and the significance of the gene copy number analysis in such patients.

Although short-stature homeobox-containing gene (SHOX ) haploinsufficiency is responsible for Léri-Weill dyschondrosteosis (LWD), the molecular defect has not been identified in approximately 20% of Japanese LWD patients. Furthermore, although high prevalence of microdeletions affecting SHOX is primarily ascribed to the presence of repeat sequences such as Alu elements around SHOX, it remains to be determined whether microdeletions are actually mediated by repeat sequences. We performed multiple ligation probe amplification (MLPA) assay in six Japanese LWD patients with apparently normal SHOX, followed by fluorescent in situ hybridization (FISH) analysis and sequencing for polymerase chain reaction (PCR) products encompassing the deletion junctions in patients with abnormal MLPA patterns. Consequently, heterozygous intragenic deletions were identified in three cases, i.e., a 5,906-bp deletion involving exons 4-5 in case 1, a 5,594-bp deletion involving exons 4-6a in case 2, and a 50,199-bp deletion involving exons 4-6b in case 3. The deletion breakpoints of cases 1 and 2 were present in nonrepeat sequences, whereas those of case 3 resided within Alu elements. The results suggest that cryptic SHOX intragenic deletions account for a small fraction of LWD and that microdeletions affecting SHOX can be generated by repeat-sequence-mediated aberrant recombinations and by nonhomologous end joining.