ESPE Abstracts (2018) 89 P-P3-181

Population Screening of Hypophosphatasia. A Metabolopathy to Consider. National Multicentric Study

Koldo Aldámiz-Echevarriaa,b, Ignacio Diez-Lopezc,d, Leonor Arranze & MJ Garcia-Barcinaf


aHU Cruces, Bilbao, Spain; bDepartament Peadiatric – Basque Country University – UPV/EHU, Bilbao, Spain; cPeadiatric Endocrinology – HU Araba, Vitoria, Spain; dDepartament Peadiatric – Basque Country University – UPV/EHU, Vitoria, Spain; eHU Donosti, San Sebastian, Spain; fHU Basurto, Bilbao, Spain


Hypophosphatasia is a congenital disease, characterized by a defect in bone and dental mineralization, secondary to a deficiency in the biosynthesis of the non-specific tissue isoenzyme of bone, liver and kidney alkaline phosphatase (TNSALP). Clinical phenotype varies with age and its clinical expression is sometimes very latent. There is a small but significant number of pediatric patients NOT diagnosed with hypophosphatasia. The values of low phosphatases may go unnoticed in routine clinical practice.

Objective: Identify those patients who gave values below normal (HYPOPHOSPHATASE) and assess whether these values can be biomarkers of rare disease. It is the first population screening study of these characteristics carried out in the region and at the national level. Establish cut-off points adjusted for age and sex for alkaline phosphatase levels in relation to rare metabolic disease. To evaluate the utility of retrospective studies in the diagnosis of rare diseases.

Material and methods: Retrospective search during a 12-month period of the very low alkaline phosphatase values at pediatric age in the databases of Central Laboratory of the hospitals participating in the study. It will be verified also present low levels in the analytical carried out in other dates to discard, since the levels of alkaline phosphatases. Detected the case, will contact the pediatrician of children to know if they have any clinical data that is indicative of this disease. Normal values were considered as Clinical Chemistry Study 2012.

Results: Population size: 16,555 Expected proportion: 0.0005%. Confidence level: 95.0%. Cases studied with initial PA +3.480, confirmed potential cases 102. Sent to genetic study and CCEE of Metabolopathies 14. Exclusion data: Anorexia nervosa, Oncology / hematology, Neuromuscular disease. Psychiatric pathology, Obesity, Traumatology, Complex cardiology Endocrinology (poly ovary, growth retardation). Cases studied (14): eight cases associated with scoliosis(traumatology), one case associated with precocious puberty, one case of short stature, one case of liver disease and myasthenia, one case of teething problems.

Conclusions: Pending genetic confirmation, we present the first study of these characteristics in our territory. Low FA levels in many cases are transient. In patients with low AF the clinic should be evaluated, in order to select the possible cases. PPH with little clinical phenotype may be more at the level of trauma. IT alert could be assessed, in values lower than 20% to the limit of normality adjusted to sex and age.

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