Oral calcium treatment in vitamin D-dependent rickets type II

Vitamin D - Dependent Rickets, Type II Case Report

AIM

The aim of this work the report of one case with vitamin D-dependent rickets, type II.

METHODS

Diagnosis has been established based on anamnesis, physical examination, laboratory findings and radiological examination.

RESULTS

A female child (age 25 months) has been hospitalized due to bone deformity, bone pain, alopecia and walking difficulties. The laboratory findings have revealed that the calcium values was low (1.20 mmol/L), phosphates in the reference value (1.30 mmol/L) the alkaline phosphatase value was quite high (852 IU/L), high value of parathyroid hormone (9.21 pmol/L), normal value of 25- hydroxyvitamin D, whereas the values of 1,25-dihydroxyvitamin D was high (185 μmol/L). Radiographic changes were evident and typical in the distal metaphysis of radius and ulna as well as in the bones of lower limbs (distal metaphysis of femur and proximal metaphysis of tibia and fibula). After treatment with calcium and calcitriol, the above mentioned clinical manifestations, laboratory test values and the radiographic changes in bones withdrew.

CONCLUSIONS

Vitamin D-dependent rickets, type II is a rare genetic recessive disease, and its treatment includes a constant use of calcium and calcitriol.

Vitamin D dependent rickets, diagnostic and therapeutic difficulties: two case reports

There are two types of vitamin D dependent rickets (VDDR) that cause rickets in children. Vitamin D dependent rickets type 1 (VDDR-I) is caused by an inborn error of vitamin D metabolism, which interferes with renal conversion of calcidiol (25OHD) to calcitriol (1,25(OH)2D) by the enzyme 1alpha-hydroxylase. Vitamin D dependent rickets type 2 (VDDR-II) is caused by a defect in the vitamin D receptor (VDR). We report cases of two African children affected by VDDR-I and VDDR-II, respectively. Establishing an early diagnosis of these genetic forms of rickets is challenging, especially in developing countries where nutritional rickets (NR) is the most common variety of the disease. A prompt diagnosis is necessary to initiate adequate treatment, resolve biochemical features and prevent complications, such as severe deformities that may require surgical intervention.

Alopecia in vitamin D-dependent rickets type II responding to 1α-hydroxycholecalciferol

A 4-year-old boy presented with rickets, alopecia and macrocephaly along with elevated serum levels of 1,25(OH)₂D₃ which was diagnostic of vitamin D-dependent rickets type II. The rickets responded to conventional doses of 1α-hydroxycholecalciferol together with oral calcium supplement and there was also improvement in the alopecia. In patients with vitamin D-dependent rickets type II with alopecia, although rickets improves with treatment, improvement in alopecia has not been reported before.

Hereditary vitamin D resistant rickets: identification of a novel splice site mutation in the vitamin D receptor gene and successful treatment with oral calcium therapy

OBJECTIVE

To study the vitamin D receptor (VDR) gene in a young girl with severe rickets and clinical features of hereditary vitamin D resistant rickets, including hypocalcemia, hypophosphatemia, partial alopecia, and elevated serum levels of 1,25-dihydroxyvitamin D.

STUDY DESIGN

We amplified and sequenced DNA samples from blood from the patient, her mother, and the patient's two siblings. We also amplified and sequenced the VDR cDNA from RNA isolated from the patient's blood.

RESULTS

DNA sequence analyses of the VDR gene showed that the patient was homozygous for a novel guanine to thymine substitution in the 5'-splice site in the exon 8-intron J junction. Analysis of the VDR cDNA using reverse transcriptase-polymerase chain reaction showed that exons 7 and 9 were fused, and that exon 8 was skipped. The mother was heterozygous for the mutation and the two siblings were unaffected.

CONCLUSIONS

A novel splice site mutation was identified in the VDR gene that caused exon 8 to be skipped. The mutation deleted amino acids 303-341 in the VDR ligand-binding domain, which is expected to render the VDR non-functional. Nevertheless, successful outpatient treatment was achieved with frequent high doses of oral calcium.

Vitamin D-dependent rickets type II in a cat

A cat with clinical signs Indicating rickets was diagnosed as having a defect of vitamin D receptors. Clinical signs had been seen from four months of age. Treatment with calcium supplementation and various forms of vitamin D did not alter plasma calcium levels or reverse skeletal lesions of lateral antebrachial bowing, lumbar spinal lordosis and costochondral beading. Analgesics were effective for relieving skeletal pain during the bone growth phase and were withdrawn when the animal reached skeletal maturity. Therapy for hip osteoarthritis was given from five years of age until the cat was euthanased at nine years of age as a result of refractory hip pain.