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X-linked hypophosphatemic rickets (XLH) is primarily characterized by renal phosphate wasting with hypophosphatemia, short stature, and bone deformity of the leg. Here we present a male case of XLH with relatively mild bone deformity caused by a mosaic mutation of the phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX). Polymerase chain reaction (PCR) direct sequencing revealed a novel in-frame deletion, NM-000444.6:c.671-685del p.Gln224-Ser228del, at exon 6 in PHEX as a mosaic pattern. This mutation was not found in any database and may result in a significant change in higher-order protein structure and function. TA cloning of the PCR product and clone sequencing estimated the mutation allele frequency at 21%. Literature review of the previously reported three cases with novel mosaic mutations in PHEX, together with the present case, suggests that the rates of the mutation allele correlate with phenotype severity to some extent. We initially treated him with nutritional vitamin D supplements and phosphate salts. However, to avoid the development of secondary/tertiary hyperparathyroidism, we had switched nutritional to active vitamin D supplementation with reduced phosphorus salts. The present report contributes to understanding the relationship between the mosaic rate, in addition to the mutation locus, of the PHEX gene, and clinical features of XLH.

Background: Skeletal dysplasias manifest various clinical symptoms. Age at onset, severity, and progression of symptoms differ even among individuals with the same diagnosis. Though necessary support in education is presumed to differ among patients with different disorders, few articles report on education in patients with skeletal dysplasias., Objective: To clarify what types of schools children with major skeletal dysplasias attend, what kind of support they needed at schools, and how the advice on such support was conveyed from medical specialists to schools., Methods: Questionnaire study on patients with achondroplasia or hypochondroplasia (A/HCH), and osteogenesis imperfecta (OI)., Results: In A/HCH childhood locomotion ability was high and most patients had received general education, irrespective of their generation. Children with OI showed a lower level of locomotion ability; only about half of them had received general education. In selecting schools, the patients received advice from pediatricians, physiatrists, and orthopedic surgeons. The degree of necessity and content of support at the schools differed between A/HCH and OI. Remodeling of the lavatory, washbasin, and chair and support during swimming lessons were common in A/HCH patients. Support in school for OI patients was more frequent and included propelling wheelchairs, assisting in the use of the bathroom, and remodeling the lavatory. Most children were restricted from participating in physical education classes., Conclusions: Locomotion ability and the necessary support at school differed between A/HCH and OI. Support and advice from medical specialists who recognize disability of patients with skeletal dysplasias may improve patients' participation and education in schools., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Osteogenesis imperfecta type IIC (OI IIC) is a rare variant of lethal OI that has been considered to be an autosomal recessive trait. Twisted, slender long bones with dense metaphyseal margins and normal vertebral bodies in OI IIC contrast with crumpled, thick long bones and multiple vertebral compression fractures in OI IIA. Here, we report on two sporadic patients with classical OI IIC and a pair of siblings, with features of OI IIC but less distortion of the tubular bones (OI dense bone variant). One case with OI IIC and the sibs had novel heterozygous mutations in the C-propeptide region of COL1A1, while the second patient with clear-cut OI IIC had no mutation in this region. Histological examination in the two sporadic cases showed a network of broad, interconnected cartilaginous trabeculae with thin osseous seams in the metaphyses. These changes differed from the narrow and short metaphyseal trabeculae found in other lethal or severe cases of OI. Our experience sheds light on the genetics and etiology of OI IIC and on its phenotypic spectrum., (Copyright © 2011 Wiley-Liss, Inc.)

Shwachman-Diamond syndrome (SDS) is a rare hereditary disorder characterized by pancreatic exocrine insufficiency, bone marrow dysfunction and skeletal changes. Recently, the cause of SDS was identified as mutations of Shwachman-Bodian-Diamond syndrome gene (SBDS) and most mutations are caused by gene conversion between SBDS and its highly homologous pseudogene. Clinical variations especially in skeletal and bone marrow abnormalities are well known in this syndrome. To study the relationship between SBDS mutation and its clinical features, we analyzed 9 Japanese patients including one sibling and detected the three different SBDS mutations in 7 patients: a mutation that disrupts the donor splice site of intron 2, deletes 8 bp of the exon 2 and produces premature termination (258+2 T > C), a dinucleotide change that replaces a lysine at 62 nd amino acid to a termination codon (183-184 TA > CT), and a 4-bp deletion that causes premature termination by frameshift (292-295 delAAAG). The 5 patients represent compound heterozygotes of the 258+2 T > C and 183-184 TA > CT mutations. One patient is a compound heterozygote of the 258+2 T > C and 292-295 delAAAG mutations, and in the remaining one case only a 258+2 T > C mutation could be detected. Thus, the 258+2 T > C and 183-184 TA > CT mutations are prevalent among Japanese patients. No mutations were found in two cases, despite the clinical features. Of the 7 patients with SBDS mutations, persistent hematologic abnormalities and skeletal changes were not observed in 3 and 2 patients, respectively. Notably, clinical variations are present even among the patients with the identical genotype: compound heterozygotes of the 258+2 T > C and 183-184 TA > CT mutations. Further study will be required to explain the clinical heterogeneity.

Autosomal dominant leukodystrophy is an extremely rare disease. Here we report on a dominantly inherited disease in a Japanese family with slowly progressive clinical course. Their symptoms and signs started in early childhood and very slowly progressed. In most patients spastic gait was the initial symptom. Neurological manifestations were characterized by pyramidal signs, ataxia, and mental deterioration. In addition to these neurological signs, the skeletal anomalies such as scoliosis and congenital hip dislocation were also present. MR images showed no abnormality in the early stage, but T2-weighted images revealed high intensity areas in the cerebral and cerebellar white matter, and the dentate nucleus in the advanced stage. Proton MR spectroscopy showed decrease of N-acetylaspartate/creatine ratio and increase of choline/creatine ratio in the advanced stage. Proton MR spectroscopy revealed normal N-acetylaspartate/creatine ratio and increase of choline/creatine ratio in the early stage. We suggested that these patients had abnormality in the white matter when MRI was still normal. We considered that intracranial demyelination was gradually progressed as the symptoms got aggravated.

Kabuki make-up syndrome (KMS, OMIM 147920) is an MCA/MR syndrome of unknown cause. It is characterized by a dysmorphic face, postnatal growth retardation, skeletal abnormalities, mental retardation, and unusual dermatoglyphic patterns. Approximately more than 350 cases have been reported from all over the world. Besides these five cardinal manifestations, joint laxity (74%), dental abnormalities (68%), and susceptibility to infections including recurrent otitis media (63%) were well recognized as other frequent features. A variety of visceral anomalies such as cardiovascular anomalies (42%), renal and/or urinary tract anomalies (28%), biliary atresia, diaphragmatic hernia, and anorectal anomaly were also reported. Some patients were said to have normal intelligence (16%) and normal heights, suggesting that they may have reproductive fitness to have their children. At least eight patients had lower lip pits with or without cleft palate, known as a feature of van der Woude syndrome. There have been 13 chromosomal abnormalities associated with KMS. However, no common abnormalities or breakpoints that possibly contribute to positional cloning of the putative KMS gene(s) are known. Although clinical manifestations of KMS are well established, its natural history, useful for genetic counseling, remains to be studied., (Copyright 2003 Wiley-Liss, Inc.)

We report here an investigation into the number of phalanges of the 2nd to 5th toes in a Japanese population. The number of phalanges in each of these toes is normally three, distal, middle and proximal. However, occasionally only two phalanges are observed. In this condition, known as symphalangism, the middle and distal phalanges are fused (synarthrosis of the distal interphalangeal joint). The incidence of symphalangism in the 488 feet was found to be 72.5% in the 5th toe, 11.9% in the 4th toe, 0.8% in the 3rd toe, and 0.0% in the 2nd toe. No left-to-right or sex differences were observed. The reported overall incidence of symphalangism in the 5th toe of the foot in the Japanese population (74.7%) is significantly higher than that in the European population (40.2%). In the present sample, the incidence of symphalangism of the 4th toe (11.9%) was significantly higher than that in Japanese population samples previously studied (4.2%).

These 62 patients with the Kabuki make-up syndrome (KMS) were collected in a collaborative study among 33 institutions and analyzed clinically, cytogenetically, and epidemiologically to delineate the phenotypic spectrum of KMS and to learn about its cause. Among various manifestations observed, most patients had the following five cardinal manifestations: 1) a peculiar face (100%) characterized by eversion of the lower lateral eyelid; arched eyebrows, with sparse or dispersed lateral one-third; a depressed nasal tip; and prominent ears; 2) skeletal anomalies (92%), including brachydactyly V and a deformed spinal column, with or without sagittal cleft vertebrae; 3) dermatoglyphic abnormalities (93%), including increased digital ulnar loop and hypothenar loop patterns, absence of the digital triradius c and/or d, and presence of fingertip pads; 4) mild to moderate mental retardation (92%); and 5) postnatal growth deficiency (83%). Thus the core of the phenotypic spectrum of KMS is rather narrow and clearly defined. Many other inconsistent anomalies were observed. Important among them were early breast development in infant girls (23%), and congenital heart defects (31%), such as a single ventricle with a common atrium, ventricular septal defect, atrial septal defect, tetralogy of Fallot, coarctation of aorta, patent ductus arteriosus, aneurysm of aorta, transposition of great vessels, and right bundle branch block. Of the 62 KMS patients, 58 were Japanese, an indication that the syndrome is fairly common in Japan. It was estimated that its prevalence in Japanese newborn infants is 1/32,000. All the KMS cases in this study were sporadic, the sex ratio was even, there was no correlation with birth order, the consanguinity rate among the parents was not high, and no incriminated agent was found that was taken by the mothers during early pregnancy. Three of the 62 patients had a Y chromosome abnormality involving a possible common breakpoint (Yp11.2). This could indicate another possibility, i.e., that the KMS gene is on Yp11.2 and that the disease is pseudoautosomal dominant. These findings are compatible with an autosomal dominant disorder in which every patient represents a fresh mutation. The mutation rate was calculated at 15.6 X 10(6).