Lamellar ichthyosis with genu valgum: unfolding the link

Abstract

SummaryWe describe a case of lamellar ichthyosis with bilateral genu valgum. The association of genu valgum with congenital ichthyosis is rare. Our patient, a 22-year-old girl, had lamellar ichthyosis and was born with a collodion membrane. She developed progressive valgus deformity of the knees of 5 years duration associated with difficulty in walking. On evaluation, she had generalised scaly skin lesions along with bilateral genu valgum and biochemical evidence of vitamin D deficiency. Skin serves as an important site for vitamin D synthesis and thus skeletal deformities secondary to vitamin D deficiency may occur in cases of congenital ichthyosis, causing a diagnostic dilemma due to the unusual association. This case serves as a reminder that clinicians need to be aware of such an association in order to prevent, appropriately diagnose and adequately treat the rare case of congenital ichthyosis with rickets and osteomalacia. BACKGROUND

Congenital lamellar ichthyosis in Tunisia associated with vitamin D rickets caused by a founder nonsense mutation in the TGM1 gene

“…In our case, the occurrence of rickets can be attributed to both nutritional vitamin D deficiency and the underlying ichthyotic disorders. Hence, children with ichthyosis may require lifelong prophylaxis of calcium and vitamin D 7. In our patient, a nonsense mutation, the c.788G>A, p.W263X in the TGM1 gene was identified, which is a founder nonsense mutation 8.…”

Generalized spiny verrucous skin with knee deformity in a 16‐year‐old girl

“…Some classical radiological features of rickets such as metaphyseal cupping and widening (wrist/ankle) were not seen in our patient, possibly because of presentation at an age when growth plate fusion had already occurred. Vitamin D deficiency should also be considered in other forms of ichthyosis; early and probably lifelong supplementation is required for prevention of rickets and osteomalacia 5 …”

Rickets in association with skin diseases and conditions: A review with emphasis on screening and prevention

“…26 Reported cases of rickets in patients with ichthyosis are summarized in Table 3. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] Rickets in patients with ichthyosis is explained by the following:…”

“…• Poor UV penetration of the skin, due to increased keratinocyte proliferation ( Figure 2B), leading to vitamin D deficiency. 31,33 • Reduced sun exposure. 27,45,46 Some forms of ichthyosiform erythroderma deteriorate during summer leading to avoidance behavior.…”