RESUMEN
A 7-year-old Japanese girl with conductive deafness and preauricular fistulae developed proteinuria. She had renal insufficiency, and ultrasound revealed bilateral small kidneys. These findings indicated that she had branchio-oto-renal (BOR) syndrome. In the present patient, we identified, by using multiplex ligation-dependent probe amplification (MLPA) analysis, a heterozygous EYA1 gene deletion comprising at least exons 5 to 7. In her parents, we did not detect any deletion in EYA1 by MLPA, so the deletion was a de novo mutation. PCR analysis and sequencing of patient DNA revealed a heterozygous approximately 17 kb EYA1 deletion starting from the eight last bases of exon 4 and proceeding to base 1,217 of intron 7. Furthermore, in place of this deleted region was inserted a 3756-bp-long interspersed nuclear elements-1 (LINE-1, L1). Accordingly, RT-PCR showed that exons 4-7 were not present in EYA1 mRNA expressed from the mutated allele. Although there are reports of L1 element insertion occurring in various human diseases, this is the first report of a large EYA1 deletion in combination with L1 element insertion.
Asunto(s)
Anomalías Múltiples/genética , Región Branquial/anomalías , Oído/anomalías , Eliminación de Gen , Péptidos y Proteínas de Señalización Intracelular/genética , Riñón/anomalías , Elementos de Nucleótido Esparcido Largo/genética , Mutagénesis Insercional/genética , Proteínas Nucleares/genética , Proteínas Tirosina Fosfatasas/genética , Anomalías Múltiples/patología , Niño , Femenino , Regulación del Desarrollo de la Expresión Génica , Humanos , Técnicas de Amplificación de Ácido Nucleico , ARN Mensajero/metabolismo , Insuficiencia Renal/genética , SíndromeRESUMEN
Deficiency of citrin due to mutations of the SLC25A13 gene causes adult-onset type II citrullinemia (CTLN2) and one type of neonatal intrahepatic cholestasis (NICCD). About half of the NICCD patients are detected based on high galactose, phenylalanine, and/or methionine concentrations on newborn mass screening (NMS). To clarify the perinatal and neonatal effects and the inconsistent results on NMS, we examined aminograms, the levels of bile acids and galactose in dried blood spots for NMS from 20 patients with NICCD. Birth weight was low for gestational age (-1.4 +/- 0.7 SD). Affected fetuses may have suffered intrauterine citrin deficiency. The first abnormality detected after birth was citrullinemia, and 19 of 20 patients had citrulline levels higher than +2 SD of controls. Tyrosine, phenylalanine, methionine, galactose, and bile acids were less affected than citrulline on d 5 after birth. Galactose and bile acids levels were increased at 1 mo in comparison with d 5 after birth due to impairment of the cytosolic NADH reducing-equivalent supply into mitochondria of hepatocytes. Patients with negative findings on NMS had low levels of total 20 amino acids. Citrulline/serine, citrulline /leucine plus isoleucine, and citrulline/total amino acids ratios, controlled for the confounding effect of low amount of total amino acids, were higher in all patients than +2 SD, +2 SD, and +3 SD of controls, respectively. NMS for citrin deficiency (frequency of homozygote with SLC25A13 mutation: 1/10,000-1/38,000 in East Asia) will be useful for clarification of the clinical course, treatment, and prevention of this disease.
