Marble brain disease in two Saudi Arabian siblings ABDULLAH MUZALEF, MOHAMMED ALSHEHRI, ABDULAZIZ AL-ABIDI* & HASSAN A. AL-TRABOLSI Departments of Pediatrics and *Surgery, Asir Central Hospital and College of Medicine, King Khalid University, Abha, Saudi Arabia (Accepted June 2005) Abstract Marble brain disease, also known as Guibaud–Vainsel syndrome, is a syndrome consisting primarily of renal tubular acidosis, cerebral calcification and osteopetrosis. The majority of reports originate from the Middle East. It is an autosomal recessive condition owing to carbonic anhydrase type II deficiency in renal and brain cells with a variant form of osteopetrosis. We report two siblings with this condition from Saudi Arabia. Both cases improved in both somatic growth and mental development after commencing treatment for renal tubular acidosis in the form of alkaline therapy and potassium supplementation. Introduction The association of osteopetrosis and renal tubular acidosis (RTA) was first described in 1972, and is also referred to as Guibaud– Vainsel syndrome or marble brain disease. 1,2 It is a rare syndrome which is manifested by increased bone density, growth failure, intra- cerebral calcifications, facial dysmorphism, mental retardation, renal tubular acidosis (RTA) and conductive hearing impair- ment. 3,4 It has autosomal recessive inheri- tance and is mostly owing to deficiency of carbonic anhydrase II (CAII). Osteopetrosis is an inherited metabolic bone disease in which a generalised accumulation of bone mass pre- vents normal development of marrow cavities and enlargement of osseous foramena. 5–7 It has been called ‘marble bone disease’ because the bone typically has an increased suscept- ibility to fracture. We describe two siblings from a remote area in the Southern Province of Saudi Arabia with osteopetrosis and RTA who also have striking facial similarity and cerebral calcifications consistent with the diagnosis of marble brain disease. Case 1 An 8-year-old boy presented initially to the neurosurgery service following trauma to the head and neck resulting in fracture of the second and third cervical vertebrae (C2 and C3). Computerised tomography (CT) scan of head and neck demonstrated diffuse cerebral calcification (Fig. 1). He was the product of an uneventful pregnancy with a normal natal and neonatal period. Because of poor activity and growth, the family sought medical advice at another general hospital during his infancy, but no records were available and before the boy’s admission the family had missed regular follow-up appointments. Because of submen- tality, he did not go to school. The parents were first-degree cousins and the boy had an older sister with growth retardation and submentality that had not been investigated. Reprint requests to: Dr Hassan A. Al-Trabolsi, Department of Pediatrics, College of Medicine, PO Box 641, Abha, Saudi Arabia. Fax: z966 7 224 7570; e-mail: haltrabolsi@hotmail.com Annals of Tropical Paediatrics (2005) 25, 213–218 # 2005 The Liverpool School of Tropical Medicine DOI: 10.1179/146532805X58175