A 4.25 year old female child ,born of a 3rd degree consanguineous marriage presented with a history of bow legs noticed by the mother since 1 year of ageShe had multiple pigmented skin lesions all over the body and an occipital scalp lesion since birth. There was no significant family history.She was small WT- 11.9 kg ( -2.51 SDS) , HT- 85.1cm (-4.41 SDS)Multiple nevi were present all over face , chest , arms & back , plus hairy nevi over back , buttock and thigh. Clinical features of rickets with leg bowing with an Intercondylar distance of 10cm were noted. Examination was otherwise normal. There was no organomegaly
Biochemistry revealed serum Ca: 2.52 mmol/L(2.2-2.6)S. PO4: 1.1 mmol/L(1.12-1.45),S.ALP: 726 U/L, Urine Creatinine – 5.7, Phosphorous – 4.4mmol/l, TRP -93 % with normal pH7.43 PCO2- 28.4mmol’l HCO3- 18.6mmol/l, normal vitamin D. FGF-23 : 6300.8 RU/ml ( <150)
MRI Brain demonstrated multiple melanin deposits in bilateral medial hippocampal and pial surfaces of cerebellum and bilateral parasagittal frontal lobes. S/O Neurocutaneous melanosis. Dermatology review melanocytic Naevus Syndrome (Congenital) with Cutis Vulgaris Gyrata
CSHS is a rare disorder, with 30 cases reported . features epidermal or melanocytic nevi and hypophosphatemic rickets with elevated levels of a serum phosphatonin, fibroblast growth factor-23 (FGF23).The epidermal nevus lesion in ENS follows the lines of Blaschko, with neurologic involvement in 50-70% of patients.Hypophosphatemic rickets is a rare manifestation. Skeletal defects manifestations include kyphoscoliosis genu valgum, clinodactyly, skeletal asymmetry, intoeing gait, microcephaly, limb reduction defects, calcaneovalgus, talipes equinovarus.Ocular abnormalities are seen in 30%.Precocious puberty, aortic coarctation, renal anomalies are rare.
Phosphate and calcitriol supplementation to maintain mineral homeostasis have been used, with a single report of burosumab use to try to control FGF23. Excision or ablation of nevi as treatment for hypophosphatemia is not advised.