Moyamoya disease presenting with tubular dysfunction in a child: pitfalls in diagnosing an atypical hyponatremic-hypertensive syndrome.

BACKGROUND: Moyamoya disease, a cause of pediatric stroke, has been shown to affect furthermore extra-cranial districts, mostly the kidney arterial site, resulting in steno-occlusive changes. Unilateral renal artery stenosis accounts for 8%-10% out of cases of renovascular hypertension in childhood, however it rarely underlies a hyponatremic-hypertensive syndrome (HHS). CASE PRESENTATION: We describe an 18-month-old boy with a recent history of polyuria and polydipsia, who presented an acute febrile gastroenteritis with neurological impairment, severe dehydration, hyponatremia, hypokalemia, kidney tubular dysfunction, and elevated aldosterone and renin even with a normal blood pressure. Fluid and electrolytes correction was performed, with complete recovery. An abdominal ultrasound displayed a smaller right kidney. A brain magnetic resonance and an electroencephalogram did not show any relevant abnormalities. Five months later, the child experienced a left-side hemiparesis after a traumatic concussion, and a severe hypertension. A brain tomography documented a cerebral ischemia. Brain and kidney angiographic studies displayed puff of smoke findings of internal right carotid artery branches and a steno-occlusive pattern of right renal artery, respectively. Hence, moyamoya disease with HHS secondary to unilateral renal artery stenosis was diagnosed. After an unsuccessful antiplatelet and antihypertensive pharmacological treatment, the boy underwent a renal angioplasty and a cerebral STA-MCA bypass (direct superficial temporal artery-to-middle cerebral artery bypass), resulting in a significant improvement of both neurological and kidney disease. CONCLUSIONS: Although the association between unilateral renal artery stenosis and HHS has been previously shown, this is the first report of atypical HHS, with hypertension preceded by tubular dysfunction, recognized in the framework of moyamoya disease.

Successful fenofibrate therapy for severe and persistent hypertriglyceridemia in a boy with cirrhosis and glycerol-3-phosphate dehydrogenase 1 deficiency.

Glycerol-3-phosphate dehydrogenase 1 deficiency is a rare autosomal recessive disorder caused by mutations in the GPD1 gene (GPD1; OMIM*138420). Very few cases are reported in literature. It usually manifests in early infancy with transient hypertriglyceridemia, hepatomegaly, steatosis, and fibrosis. We report the case of a 16-year-old boy followed since the age of 1 year for hepatomegaly, elevated liver enzymes, and persistent hypertriglyceridemia. Abdominal ultrasound showed diffuse liver echogenicity and liver biopsy disclosed cirrhosis with micro and macrovesicular steatosis. Next-generation sequencing for metabolic and genetic liver diseases was conducted with the identification of the homozygous mutation c.895G>A in GPD1 gene resulting in the aminocidic substitution p.G299R. Considering the persistent and progressive increase of plasma triglycerides, fenofibrate treatment was started at 15 years of age allowing triglyceride level reduction in the following 1-year follow-up.