This article reported the clinical features of one child with infantile hypophosphatasia (HPP) and his pedigree information. The proband was a 5-month-old boy with multiple skeletal dysplasia (koilosternia, bending deformity of both radii, and knock-knee deformity of both knees), feeding difficulty, reduction in body weight, developmental delay, recurrent pneumonia and respiratory failure, and a significant reduction in blood alkaline phosphatase. Among his parents, sister, uncle, and aunt (other family members did not cooperate with us in the examination), his parents and aunt had a slight reduction in alkaline phosphatase and his aunt had scoliosis; there were no other clinical phenotypes or abnormal laboratory testing results. His ALPL gene mutation came from c.228delG mutation in his mother and c.407G>A compound heterozygous mutation in his father. His aunt carried c.228delG mutation. The c.407G>A mutation had been reported as the pathogenic mutation of HPP, and c.228delG mutation was a novel pathogenic mutation. Hypophosphatasia is caused by ALPL gene mutation, and ALPL gene detection is an effective diagnostic method. This study expands the mutation spectrum of ALPL gene and provides a theoretical basis for genetic diagnosis of this disease.
Alkaline Phosphatase ; genetics ; Carrier Proteins ; chemistry ; Female ; Heterozygote ; Humans ; Hypophosphatasia ; etiology ; genetics ; Infant ; Male ; Mutation ; Pedigree

OBJECTIVE: To explore the genetic basis for a girl featuring bone and tooth mineralization disorder, premature deciduous teeth, rickets and short stature. METHODS: Genomic DNA was extracted and subjected to high-throughput whole exome sequencing. Suspected variants were confirmed by Sanger sequencing. Impact of potential variants was analyzed with bioinformatic software. RESULTS: The child was found to carry compound heterozygous missense variants of the ALPL gene, including c.1130C>T (p.A377V), a known pathogenic mutation inherited from her father, and c.1300G>A (p.V434M) inherited from her mother, which was unreported previously and predicted to be likely pathogenic based on standards and guidelines from the American College of Medical Genetics and Genomics (PM2+PM5+PP3+PP4). CONCLUSION The compound heterozygous variants of c.1130C>T (p.Ala377Val) and c.1300G>A (p.Val434Met) of the ALPL gene probably underlay the disease in this child. Above finding has enriched the spectrum of ALPL gene variants.
Alkaline Phosphatase ; Child ; Female ; Genomics ; High-Throughput Nucleotide Sequencing ; Humans ; Hypophosphatasia/genetics* ; Mutation ; Whole Exome Sequencing

This paper summarizes the clinical features, causative genes and treatment progress of patients with rickets-like genetic diseases, including X-linked hypophosphatemic rickets (XLH), hypophosphatasia, achondroplasia, vitamin D-dependent rickets, pycnodysostosis and ectodermal dysplasia, who visited the pediatric or child health clinic due to the symptoms of rickets, including bow legs, delayed closure of the anterior fontanelle, and sparse hair. Children with XLH usually go to hospital for bow legs and short stature, and biochemical evaluation reveals significantly low serum phosphorus so it is easily diagnosed. This disease is treated using phosphate mixture and 1,25(OH)2D3, which is different from the treatment of nutritional vitamin D deficiency rickets. Hypophosphatasia is characterized by a significant decrease in serum alkaline phosphatase, as well as normal serum calcium and phosphorus. The disease is caused by mutations in TNSALP gene. Patients with achondroplasia show short-limbed dwarfism and special face in addition to bow legs, but with normal serum calcium, phosphorus and alkaline phosphatase. Bone X-ray and FGFR3 gene test contribute to the diagnosis. Vitamin D-dependent rickets is an autosomal recessive disease, and active vitamin D supplement is effective in treatment of the disease. Patients with pycnodysostosis may be first seen at hospital because of large anterior fontanelle; in addition, they also show obtuse mandibular angle, dental abnormalities and dysplastic nails, which are caused by mutations in TSK gene. Children with ectodermal dysplasia may see a doctor for sparse hair, and they are easily misdiagnosed with nutritional vitamin D deficiency rickets. Ectodermal dysplasia is related to EDA, EDAR, EDARADD and WNT 10A genes.
Achondroplasia ; genetics ; therapy ; Ectodermal Dysplasia ; genetics ; therapy ; Familial Hypophosphatemic Rickets ; genetics ; therapy ; Humans ; Hypophosphatasia ; genetics ; therapy ; Pycnodysostosis ; genetics ; therapy

OBJECTIVETo screen potential mutations of PHEX gene in a family featuring hypophosphatemic rickets in order to confirm the molecular diagnosis and pathogenetic mechanism.

METHODSGenomic DNA was extracted from peripheral venous blood samples. DNA sequence of PHEX gene was derived from UCSC database, and primers for its coding region were designed with Primer premier 5.0. Potential mutations were detected with PCR amplification and DNA sequence analysis.

RESUTLSA mutation was identified in intron 6 of the PHEX gene in the proband and his mother.

CONCLUSIONThe c.732+1G>T mutation underlies the hypophosphatemic rickets in this family.

Adult ; Base Sequence ; Child ; Female ; Humans ; Hypophosphatasia ; enzymology ; genetics ; Introns ; Male ; Molecular Sequence Data ; Mutation ; PHEX Phosphate Regulating Neutral Endopeptidase ; genetics ; Pedigree