X–Linked Hypophosphatemic Rickets–Case Report from Latvia

Presentation Number: FRI-217
Date of Presentation: March 6th, 2015

Maija Mukane*1 and Ingvars Rasa2
1Riga Stradins University, Riga East Clinical University Hospital, Latvian Osteoporosis and Bone Metabolism Diseases Association, Riga, Latvia, 2Riga East Clinical University Hospital, Riga Stradins University, Latvian Osteoporosis and Bone Metabolism Diseases Association, Riga, Latvia

Abstract

X–linked hypophosphatemic rickets (XLH) is a dominant disorder with a prevalence of approximately one case per 20 000 live births. Latvia is one of the European Union countries, and there were approximately 2 million people living in 2011.Theoretically there should be diagnosed 100 cases of the XLH, but during the time from 2011 till 2014 no other cases were diagnosed or reported.

Although clinical features of the disease present soon after birth, case report shows patient with first diagnosed XLH at the age of 26 years in 2011. This young female sustained a muscle weakness in upper legs and upper arms, pain in left hip, left knee and back. Above–mentioned symptoms patient had from 2006, but the disease’s breakdown was in March, 2011 when she attended Hospital in the first time. There was no approved related congenital pathology in family history, however patient’s mother probably had 1.25(OH)2D vitamin resistance.

In–hospital laboratory findings were the following – serum calcium 2.24 mmol/L (reference range 2.10–2.60 mmol/L), parathyroid hormone 25.0 pg/mL (reference range 12.0–72.0 pg/mL) and serum phosphorus level was 0.51 mmol/L (reference range 0.80–1.60 mmol/L). CT and MRI scans of pelvic bones, knee and sacroiliac joints and whole body bone scintigraphy scan with technetium99m were made and multiple fractures were found (consolidated fractures of 7th and 8th ribs in the right side, 8thrib in the left side, multiple sacrum fractures and left hip fracture with pseudarthrosis). After hospitalization additional laboratory analyses showed low 25(OH)D level – 14.0 ng/mL (reference range 20.00–55.0 ng/mL), sufficient 1.25(OH)2D level – 51.20 pg/mL (reference range 19.60–54.30 pg/mL), high alkaline phosphatase level – 172.0 U/L (reference range <117.0 U/L) and high alkaline phosphatase bone fraction level – 51.2 μg/L (reference range 3.0–19.0 μg/L). Bone biopsy from crista iliacashowed thin cortical bone, trabecular bone atrophy and bone marrow fibrosis. Considering laboratory and instrumental findings XLH were suspected, but there was no possibility to make genetic analysis of the disease in Latvia.

Prescribed treatment was sodium phosphate 500 mg four times daily and 5000 international units of cholecalciferol daily per orally. In 2011 left hip replacement was made.

Till now patient’s follow–up continues, last laboratory findings in 2014 were the following – serum calcium 2.33 mmol/L (normal), phosphorus level 1.37 mmol/L (normal), 25(OH)D vitamin 49.9 ng/mL (normal), alkaline phosphatase 122.0 mmol/L (above reference range). In 2014 patient had first pregnancy and delivered healthy child.

Although not always there is a possibility to prove the diagnosis using genetic analysis, considering clinical, laboratory and instrumental findings it is possible to support patient and improve life quality.

 

Nothing to Disclose: MM, IR