A NOVEL CYP27B1 GENE MUTATION: A RARE CAUSE OF TREATABLE VITAMIN D DEPENDENT RICKETS TYPE1A: A CASE REPORT AND REVIEW OF LITERATURE

Dr. Muneera Al Shareef*, Dr. Samia A. Bokhari, Dr. Shaza Khan, Dr. Mohammed Galal, Dr. Hamdy Alkady, Dr. Islam Goudah

ABSTRACT

Background: Vitamin D deficiency is the most common cause of rickets followed by liver and renal diseases that affect vitamin D metabolism. Rare genetic errors of vitamin D metabolism can cause rickets. One of the three rare genetic errors of vitamin D metabolism is CYP27B1 gene which encodes 1α-hydroxylase. It is the genetic base for vitamin D dependent rickets type1(VDDR-1). Case Presentation: A 22year Saudi woman presented with the history of slow development in growth, joint pains and difficulty in walking since early childhood. She diagnosed to have rickets with typical physical and radiological features. She was treated with calcium and vitamin D supplements in different hospitals. As her symptoms persisted she was referred to our endocrine department. On further investigations she had typical biochemical features of VDDR- Type-1. Genetic studies revealed the mutation in CYP27B1 gene, confirming the diagnosis of VDDR-type 1 rickets. She was treated with alpha calcitriol and calcium supplements with improvement in her symptoms. Conclusion: A novel mutation of the CYP27B1 gene is a rare cause of vitamin dependent rickets. It may be confused with vitamin D deficiency rickets or hypophosphetemic rickets and treated inappropriately. If biochemical investigations and typical radiological features suggestive of genetic errors of vitamin D metabolism, should be investigated for rare genetic errors of vitamin D metabolism by appropriate genetic studies for correct diagnosis and treatment.

Keywords: 1, 25 Dihydroxyvitamin D3, Vitamin D dependent rickets type 1, CYP27B1 gene mutation.