The clinical spectrum of MAS is comparable across patients seen in different geographic settings or by diverse pediatric subspecialists. There was a disparity in the therapeutic choices among physicians that underscores the need to establish uniform therapeutic protocols.

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Description of six Colombian karyomorphs is completed through an extensive cytogenetic characterization of 35 Aotus (owl monkeys) specimens. The description of a new karyomorph for Colombian Aotus by chromosome on Q, G, R, and C, sequential banding is included. Pairs of karyomorphs 2 and 3 and 6 and 9 with 2n of 54, and 50, respectively, as well as karyomorphs 7 and 8 with 46 and 58 chromosomes were strongly suspected to represent different species on the grounds of large karyotypic differences. A proposal for a chromosome nomenclature of Aotus karyomorphs that aims to clarify Aotus taxonomy is presented which achieves a precise correspondence of different banding patterns, based on Q, G, R, and C sequential banding and chromosome measurements. Although our contribution is not a universal nomenclature system, unique criteria for chromosome denomination within Aotus karyomorphs are established. Previous systems of chromosome nomenclature have not successfully addressed the nomenclature of chromosomes of the same karyotype. Am. J. Primatol. 44:255–275, 1998. © 1998 Wiley‐Liss, Inc.

BackgroundAutosomal recessive distal renal tubular acidosis (dRTA) is a rare disease characterized by a hyperchloremic metabolic acidosis with normal anion gap, hypokalemia, hypercalciuria, hypocitraturia, nephrocalcinosis, and conserved glomerular filtration rate. In some cases, neurosensorial deafness is associated. dRTA is developed during the first months of life and the main manifestations are failure to thrive, vomiting, dehydration, and anorexia.MethodsNine unrelated families were studied: seven children, a teenager, and an adult with dRTA. Hearing was preserved in four children. Coding regions of the genes responsible for recessive dRTA were analysed by Sanger sequencing.ResultsMolecular defects were found in the genes ATP6V1B1 and ATP6V0A4. We identified three homozygous variants in ATP6V1B: a frameshift mutation (p.Ile386Hisfs*56), a nucleotide substitution in exon 10 (p.Pro346Arg), and a new splicing mutation in intron 5. Three patients were homozygous for one novel (p.Arg743Trp) and one known (p.Asp411Tyr) missense mutations in the ATP6V0A4 gene. Three patients were compound heterozygous: one proband displayed two novel mutations, the frameshift mutation p.Val52Metfs*25, and a large deletion of exons 18–21; two probands showed the missense mutation p.Asp411Tyr and as a second mutation, p.Arg194Ter and c.1691+2dup, respectively.Conclusion ATP6V0A4 and ATP6V1B1 genes were involved in recessive dRTA of Mexican families. All ATP6V1B1 mutations detected were homozygous and all patients developed sensorineural hearing loss (SNHL) early in infancy. ATP6V0A4 mutations were found in one infant and three children without SNHL, and in one teenager and one adult with SNHL confirming the phenotypic variability in this trait. The mutation p.Asp411Tyr detected in four Mexican families was due to a founder effect. Screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA in this population.

Objective To develop a standardized steroid dosing regimen (SSR) for physicians treating childhood‐onset systemic lupus erythematosus (SLE) complicated by lupus nephritis (LN), using consensus formation methodology. Methods Parameters influencing corticosteroid (CS) dosing were identified (step 1). Data from children with proliferative LN were used to generate patient profiles (step 2). Physicians rated changes in renal and extrarenal childhood‐onset SLE activity between 2 consecutive visits and proposed CS dosing (step 3). The SSR was developed using patient profile ratings (step 4), with refinements achieved in a physician focus group (step 5). A second type of patient profile describing the course of childhood‐onset SLE for ≥4 months since kidney biopsy was rated to validate the SSR‐recommended oral and intravenous (IV) CS dosages (step 6). Patient profile adjudication was based on majority ratings for both renal and extrarenal disease courses, and consensus level was set at 80%. Results Degree of proteinuria, estimated glomerular filtration rate, changes in renal and extrarenal disease activity, and time since kidney biopsy influenced CS dosing (steps 1 and 2). Considering these parameters in 5,056 patient profile ratings from 103 raters, and renal and extrarenal course definitions, CS dosing rules of the SSR were developed (steps 3–5). Validation of the SSR for up to 6 months post–kidney biopsy was achieved with 1,838 patient profile ratings from 60 raters who achieved consensus for oral and IV CS dosage in accordance with the SSR (step 6). Conclusion The SSR represents an international consensus on CS dosing for use in patients with childhood‐onset SLE and proliferative LN. The SSR is anticipated to be used for clinical care and to standardize CS dosage during clinical trials.