Lowe syndrome: a single center's experience in Korea / 소아과

PURPOSE: Lowe syndrome is a rare, X-linked recessive disorder caused by mutations in the OCRL gene. It involves multiple anatomic systems, particularly the eyes, central nervous system, and kidneys, and leads to profound growth failure and global developmental delay. This study evaluated the clinical and genetic characteristics of Korean patients with Lowe syndrome. METHODS: The clinical findings and results of genetic studies were reviewed for 12 male patients diagnosed with Lowe syndrome at a single medical institution. RESULTS: The mean age of the patients at presentation was 2.2 months (range, 0-4 months), although the diagnosis was delayed by a mean of 2.8 years (range, 0-9.7 years). The mean follow-up period was 9.0 years (range, 0.6-16.7 years). Nine mutations in OCRL were identified in 11 patients (92%), with three novel mutations. The main presentation was congenital cataract in both eyes necessitating early cataract removal in the 11 patients with impaired visual acuity. Profound short stature and developmental delay were observed in all patients, and seizures occurred in 50% of the patients. All patients suffered from proximal renal tubular dysfunction, and one patient developed chronic renal failure. Other manifestations included pathologic fracture (50%), cutaneous cysts (42%), and cryptorchidism (42%). However, there was no bleeding tendency, and none of the patients died during the study period. CONCLUSION: This study describes the clinical and genetic characteristics of Korean patients with Lowe syndrome. The observations are helpful for understanding the natural courses of Lowe syndrome and for appropriate genetic counseling.

Síndrome de Lowe: relato de cinco casos / Lowe syndrome: report of five cases

INTRODUÇÃO: A síndrome de Lowe, ou distrofia oculocerebrorrenal (OCRL), tem herança recessiva ligada ao cromossomo X. Apresenta-se com catarata, glaucoma, atraso no desenvolvimento neuropsicomotor (DNPM), déficit cognitivo e síndrome de Fanconi. OBJETIVO: Descrever a evolução de cinco pacientes pediátricos atendidos no ambulatório de tubulopatias do Departamento de Nefrologia Pediátrica da Universidade Federal de São Paulo-Escola Paulista de Medicina Unifesp (Unifesp-EPM). MÉTODOS: Estudo retrospectivo de cinco pacientes masculinos atendidos no ambulatório de tubulopatias. RESULTADOS: A média de idade na primeira consulta foi de 76,5 meses; o tempo médio de acompanhamento, de 30,5 meses (mínimo de 8 meses e máximo de 53 meses). Os sintomas e os sinais clínicos incluíram catarata e nistagmo. Atraso no DNPM e déficit de peso e de estatura estiveram presentes em todos os casos, bem como poliúria, polidipsia, constipação, acidose metabólica, fosfatúria, bicarbonatúria, proteinúria, hipercalciúria e hiperuricosúria. Nefrocalcinose foi identificada em um paciente; litíase renal, em três; e redução do tamanho renal, em dois. Fraturas patológicas e raquitismo foram observados em dois pacientes; rarefação óssea e atraso na idade óssea, em todos os pacientes. Um deles apresentou redução no ritmo de filtração glomerular. Terapeuticamente, todos receberam álcalis, fósforo e reposição com vitamina D, além de orientação dietética para suas necessidades. CONCLUSÃO: Este estudo preconiza a necessidade do diagnóstico precoce e do acompanhamento médico e nutricional desses pacientes para evitar complicações relacionadas com distúrbios metabólicos.

INTRODUCTION: Lowe Syndrome, or Oculocerebrorenal Dystrophy (OCRL), has a recessive inheritance linked to X chromosome. It presents cataracts and glaucoma, delay in neuropsychomotor development, cognitive deficits, and renal Fanconi syndrome. OBJECTIVE: Describe five patients with OCRL, attended at Tubulopathy outpatient clinic. METHOD: We performed a retrospective assessment of 5 male patient clinical charts of OCRL patients. RESULTS: Mean age at first consultation was 76.5 and mean follow up interval was 30.5 months (8-53 months). Symptoms and clinical signs included cataracts and nystagmus. Neuropsychomotor development and weight and height deficits were present in whole cases, as well as polyuria, polydipsia, and intestinal constipation, metabolic acidosis, phosphaturia, bicarbonaturia, proteinuria, hypercalciuria, hyperuricosuria. Nephrocalcinosis was identified in one, renal lithiasis in three, and reduced kidney size in two patients. We found pathological fractures and rachitism in two, bone rarefaction and delay of bone age in all of the patients. One patient presented a reduction in the rhythm of glomerular filtration. Therapeutically, all patients received alkali, phosphorus and vitamin D reposition in addition to a dietary orientation adequate to their needs. CONCLUSION: This study emphasizes the importance of early diagnosis and medico-nutritional followup, to avoid complications related to metabolic disturbances.

Two Cases of Oculocerebrorenal Syndrome in Two Brothers Diagnosed after Congenital Cataract Surgery

PURPOSE: We report two cases of brothers diagnosed with oculocerebrorenal syndrome after binocular congenital cataract surgery. METHODS: Two brothers who had undergone surgeries for congenital cataracts showed growth retardation, proteinuria, and generalized tonic seizures. The patients were referred to the pediatrics department and evaluated for systemic diseases and genetic counseling. RESULTS: Two brothers had renal tubular dysfunction characterized by hypercalciuria and hyperphosphaturia. The older brother had multiple microcalcifications on both kidneys, and ischemic injury with general dysfunction of the brain. Genetic analysis of brothers and their mother showed a new mutation of P799L in the region of the chromosome Xq25-26.1 locus. The two brothers were diagnosed with oculocerebrorenal syndrome of Lowe (OCRL). CONCLUSIONS: In cases of patients with congenital cataracts, the evaluation of systemic disease including genetic abnormality should be considered whenever systemic symptoms such as growth retardation, proteinuria or seizure are found.

Two Cases of Oculocerebrorenal Syndrome of Lowe

Oculocerebrorenal syndrome of Lowe(OCRL) is a rare X-linked disorder characterized by congenital cataract(oculo-), hypotonia, developmental delay, cognitive impairment(cerebro-), renal tubular dysfunction(renal), and growth retardation. Recently, the defective gene, OCRL-1 gene encoding [PtdIns(4,5)P2] 5-phosphatase, was cloned with mutations identified in patients. Although there have been about 200 cases of OCRL reported in English literature, only three reports have been published in our country including two from an ophthalmologic point of view. This is a case report of two patients diagnosed with OCRL at our hospital. The diagnosis was based on characteristic clinical manifestations involving three major systems(eyes, central nervous system and kidneys) and MRI findings of the brain. There are no specific therapy for this disorder yet, and we provided ophthalologic treatment for congenital cataract, rehabilitation therapy for neurologic symptoms, and supportive therapy for renal Fanconi syndrome. We expect that a molecular genetic diagnosis and gene therapy will be available in the near future.