This paper summarizes the clinical features, causative genes and treatment progress of patients with
rickets-like
genetic diseases, including
X-linked hypophosphatemic rickets (XLH),
hypophosphatasia,
achondroplasia,
vitamin D-dependent
rickets,
pycnodysostosis and
ectodermal dysplasia, who visited the pediatric or child health clinic due to the symptoms of
rickets, including
bow legs, delayed closure of the anterior fontanelle, and sparse hair. Children with XLH usually go to hospital for
bow legs and short stature, and biochemical evaluation reveals significantly low serum
phosphorus so it is easily diagnosed. This disease is treated using
phosphate mixture and
1,25(OH)2D3, which is different from the treatment of nutritional
vitamin D deficiency rickets.
Hypophosphatasia is characterized by a significant decrease in serum
alkaline phosphatase, as well as normal serum
calcium and
phosphorus. The disease is caused by mutations in TNSALP gene. Patients with
achondroplasia show short-limbed
dwarfism and special face in addition to
bow legs, but with normal serum
calcium,
phosphorus and
alkaline phosphatase. Bone X-ray and FGFR3 gene test contribute to the diagnosis.
Vitamin D-dependent
rickets is an autosomal recessive disease, and active
vitamin D supplement is effective in treatment of the disease. Patients with
pycnodysostosis may be first seen at hospital because of large anterior fontanelle; in addition, they also show obtuse mandibular angle, dental abnormalities and dysplastic nails, which are caused by mutations in TSK gene. Children with
ectodermal dysplasia may see a doctor for sparse hair, and they are easily misdiagnosed with nutritional
vitamin D deficiency rickets.
Ectodermal dysplasia is related to EDA, EDAR, EDARADD and WNT 10A genes.