Test Directory
Test Code | ||||||||||||||||||||||||||||||
C1565 | ||||||||||||||||||||||||||||||
Test Name | ||||||||||||||||||||||||||||||
Hypophosphatasia, Infantile, Childhood & Adult Types | ||||||||||||||||||||||||||||||
CPT Codes | ||||||||||||||||||||||||||||||
81479 | ||||||||||||||||||||||||||||||
Expected Turnaround Time | ||||||||||||||||||||||||||||||
Typically 2 to 4 weeks from receipt of a sample in the laboratory. All cases involving ongoing pregnancies will be expedited. | ||||||||||||||||||||||||||||||
Clinical Utility | ||||||||||||||||||||||||||||||
Genetic analysis to provide a molecular diagnosis of hypophosphatasia caused by the ALPL gene. Features include blue sclera, bowed short limbs, metaphyseal cupping, poorly formed teeth, a small thorax, and lack of skeletal ossification with fractures. There are several forms of hypophosphatasia caused by the ALPL gene which vary in severity and onset, though some individuals may be asymptomatic. Recommended for individuals with a personal and/or family history of hypophosphatasia to ensure appropriate treatment and establish recurrence risk for family members. | ||||||||||||||||||||||||||||||
Specimen and Container Info | ||||||||||||||||||||||||||||||
Non-Prenatal Specimens
Prenatal Specimens Either specimen type below is acceptable.
NOTE: For specimens from outside of North America, the preferred specimen type is Genomic DNA. HNL Genomics does not recommend shipping whole blood or cultured cells from any location other than the United States, Canada, or Mexico. |
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Methodology | ||||||||||||||||||||||||||||||
Next Generation Sequencing and Copy Number Variation Analysis | ||||||||||||||||||||||||||||||
Performing Location | ||||||||||||||||||||||||||||||
Genomics - Snowdrift | ||||||||||||||||||||||||||||||
Description | ||||||||||||||||||||||||||||||
Hypophosphatasia is clinically divided into three types, all caused by defects in the ALPL gene.
Hypophosphatasia, infantile (MIM 241500), is a severe form with onset in utero or before 6 months of age. Inheritance is autosomal recessive. Patients may have blue sclera, bowed short limbs, metaphyseal cupping, bone spurs of the ulna and fibula, poorly formed teeth, small thoracic cage with rachitic ribs, lack of skeletal ossification with fractures, craniosynostosis, skin dimples over the apex of long bone angulations and platyspondyly. Mental retardation or development delay may also be a feature. This disorder overlaps with osteogenesis imperfecta and achondrogenesis type IA. Laboratory abnormalities include: hypercalcemia, hypercalciuria, phosphoethanolaminuria, decreased tissue and serum alkaline phosphatase and mildly elevated phosphoethanolamine. Plasma and urine inorganic pyrophosphate may be elevated. Hypophosphatasia, childhood (MIM 241510), has a more gradual and later onset. Inheritance is also autosomal recessive. Patients share many features with the infantile form including short stature, rachitic ribs, bowed legs, skin dimples and premature loss of teeth. They may also display craniostenosis, dolichocephaly, frontal bossing, proptosis and characteristic metaphyseal radiolucency. Presentation occurs beyond 6 months of age and there may be delayed onset of walking. Laboratory abnormalities include: low alkaline phosphatase, phosphoethanolaminuria and elevated plasma and urine inorganic pyrophosphate. Hypophosphatasia, adult type (MIM 146300) presents in middle age and may actually be asymptomatic. Inheritance can be autosomal dominant or recessive with compound heterozygosity. Patients may suffer premature tooth loss, skeletal abnormalities, osteoporosis, recurrent fractures or long bone pseudofractures, with bowed legs, bone pain or arthropathy and chondrocalcinosis. Laboratory abnormalities are similar to those described under the childhood variant. |
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Testing Schedule | ||||||||||||||||||||||||||||||
Monday-Friday | ||||||||||||||||||||||||||||||
Genes | ||||||||||||||||||||||||||||||
ALPL | ||||||||||||||||||||||||||||||
MIM | ||||||||||||||||||||||||||||||
241500 | ||||||||||||||||||||||||||||||
Disease Group | ||||||||||||||||||||||||||||||
Skeletal Disorders, Metabolic and Endocrine |
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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