A multicenter investigation with D-FISH BCR/ABL1 probes.

Twenty-eight laboratories evaluated a new fluorescence in situ hybridization (FISH) strategy for chronic myeloid leukemia. In a three-part study, bcr/abl1 D-FISH probes were used to study bone marrow specimens. First, laboratories familiarized themselves with the strategy by applying it to known normal and abnormal specimens. Then, collectively the laboratories studied 20 normal and 20 abnormal specimens blindly and measured workload. Finally, each laboratory and two experts studied six serial dilutions with 98-0% abnormal nuclei. Using the reported normal cutoff of < 1% abnormal nuclei, participants reported no false-negative cases and 15 false-positive cases (1-6.6% abnormal nuclei). Results provided by participants for serial dilutions approximated the expected percentages of abnormal nuclei, but those from the experts exhibited greater precision. The clinical sensitivity, precision, nomenclature, workload, recommendations for training, and quality assurance in methods using D-FISH in clinical practice are discussed.

A boy with choanal atresia and cardiac defect: Burn-McKeown syndrome?

We report on a child we believe may have the same condition described in five children by Burn et al., in 1992 (Clin Dysmorphol 1:137-144). Component manifestations include choanal atresia, cardiac defects, prominent ears, hearing loss, and minor facial anomalies. Our patient also has rather significant short stature, thus adding to the variable phenotype of this condition.

The role of magnesium in the pathogenesis of bone disease in childhood cholestatic liver disease: a preliminary report.

BACKGROUND: Magnesium deficiency may contribute to the metabolic bone disease that complicates chronic cholestatic liver disease. We hypothesized that magnesium deficiency alters vitamin D metabolism by decreasing parathyroid hormone (PTH) response, resulting in decreased serum osteocalcin and decreased bone accretion. METHODS: Nine subjects, age 3-22 years, with cholestatic liver disease were evaluated with the magnesium retention test. The response of PTH, 1,25(OH)2 vitamin D, and osteocalcin to provocative stimuli and dual x-ray absorptiometry measurement of bone mineral density (BMD) of the lumbar spine were assessed. Thereafter, subjects were treated with oral magnesium supplements. RESULTS: All nine subjects were magnesium depleted. Repletion with magnesium was successful in seven subjects, and required 4 to 31 (median 14) months with doses of 6 to 34 (median 11) mg/kg/day. Baseline serum PTH was significantly reduced in the cholestatic subjects compared to 15 age-matched controls. Comparison of baseline to repleted provocative testing was performed in six Mg-repleted subjects. Osteocalcin response increased significantly (p = 0.048) with repletion, while PTH response increased (p = 0.061). Lumbar spine BMD increased modestly with repletion (p = 0.093). CONCLUSIONS: This preliminary report suggests that magnesium depletion is extremely common in children with chronic cholestasis. We speculate that magnesium supplementation may be warranted to forestall the progression of metabolic bone disease in chronic cholestasis.

Macrocephaly-cutis marmorata telangiectatica congenita: a distinct disorder with developmental delay and connective tissue abnormalities.

We describe 13 unrelated children with abnormalities of somatic growth, face, brain, and connective tissue including vasculature. Although the condition in these children falls under the general group of disorders known as cutis marmorata telangiectatica congenita (CMTC), the constellation of abnormalities appears to constitute a distinct and easily recognizable phenotype within this general group. In contrast to most children reported with CMTC, children in this subgroup have a high risk for neurologic abnormalities, including developmental delay, mental retardation, megalencephaly, and hydrocephalus. Early recognition of this condition is important for appropriate surveillance for known complications and parental counseling.

A translocation interrupts the COL5A1 gene in a patient with Ehlers-Danlos syndrome and hypomelanosis of Ito.

Ehlers-Danlos syndrome (EDS) is a genetically and pathogenetically heterogeneous group of disorders of which at least 11 types have been described. All are connective tissue disorders characterized by defects of the skin, ligaments and blood vessels with the clinical spectrum ranging from innocuous findings to lethality. Mutations in the genes encoding the major fibrillar collagen types I and III have been demonstrated in EDS types VII and IV, respectively, while mutations in the lysyl hydroxylase and ATP7A genes, with roles in collagen cross-linking, are responsible for EDS types VI and IX. The biochemical and molecular bases for the most common forms of EDS (types I, II and III) are unknown. Here, we describe a balanced translocation between chromosome 9 and an X chromosome that disrupts the minor fibrillar collagen type V gene COL5A1 in a patient with both EDS type I and hypomelanosis of Ito. The breakpoint occurs at 9q34 within COL5A1 intron 24 and interestingly, within a LINE-1 (L1) element at Xp21.1. A fusion mRNA between COL5A1 and an Alu sequence is produced, but no aberrant protein is detectable. Rather, the amount of type V collagen is reduced in the patient's fibroblasts, suggesting haploinsufficiency as a cuase of the phenotype. This demonstrates that a mutation in a type V collagen gene, COL5A1, results in EDS type I, and shows the involvement of L1 sequences in a constitutional chromosomal translocation. Because collagen type V is a heteromorphic protein in which molecules may be composed of polypeptides encoded by three COL5A genes, this suggests all three genes as candidates for mutations in EDS.

Oculoauriculofrontonasal syndrome: report of another case and review of differential diagnosis.

We report a male with features of frontonasal dysplasia, but also with ocular and auricular defects. This child most likely has oculoauriculofrontonasal syndrome, an autosomal recessive syndrome first described in 1981. We also review the literature on this syndrome, and discuss differential diagnosis.

Craniodigital syndromes: report of a child with Filippi syndrome and discussion of differential diagnosis.

We describe a boy with low birth weight, congenital microcephaly, multiple minor facial anomalies, cleft palate, soft tissue syndactyly of fingers and toes, and moderate to severe mental retardation. Literature review suggested 6 possible diagnoses, including Scott craniodigital syndrome, Chitayat syndrome, Filippi syndrome, Zerres syndrome, Kelly syndrome, and Woods syndrome. Each has as part of the phenotype craniofacial anomalies and soft tissue syndactyly of fingers and toes; and superficially, distinction among the 6 may be difficult. However, based on the phenotype analysis we performed, we conclude that our patient has Filippi syndrome, and thus is the first reported case from the United States.

Downregulation of taurocholate transport by ileal BBM and liver BLM in biliary-diverted rats.

The enterohepatic circulation of bile salts may be substrate dependent. We hypothesize that decreased intestinal delivery of bile salts results in downregulation of ileal and hepatocyte bile salt transport in the biliary-diverted rat. Maximal velocity (Vmax) of taurocholate transport by ileal brush-border membrane (BBM) vesicles was downregulated in the bile-diverted animals by 45.5% (559.9 +/- 57.8 pmol.mg protein-1.min-1 in bile-diverted rats vs. 1,026.6 +/- 170.9 pmol.mg protein-1.min-1 in shams). Similarly, taurocholate transport Vmax by hepatocyte basolateral membrane (BLM) was downregulated by 37.8% (2.62 +/- 0.18 pmol.mg protein-1.min-1 in bile-diverted rats vs. 6.93 +/- 0.41 pmol.mg protein-1.min-1 in shams). Cholesterol content (mumol/mg protein) of the membranes was increased in both BBM (0.478 +/- 0.055 vs. 0.272 +/- 0.029) and BLM (0.410 +/- 0.052 vs. 0.294 +/- 0.044) in diverted rats compared with shams. Fluorescence anisotropy was significantly higher in diverted animals compared with shams for both BBM (0.2333 +/- 0.001 vs. 0.2120 +/- 0.004) and BLM (0.1524 +/- 0.002 vs. 0.1426 +/- 0.005). We conclude that biliary diversion in the rat leads to downregulation of both ileal BBM and hepatocyte BLM taurocholate transport. Alterations in transporter expression caused by diversion may, in part, be mediated by changes in membrane lipid composition or fluidity.

Fine mapping of X-linked clasped thumb and mental retardation (MASA syndrome) in Xq28.

The MASA syndrome is an X-linked disorder with mental retardation, spastic paraparesis, and adducted thumbs as the most characteristic features. We performed linkage analysis, using Xq28 markers, on a large MASA syndrome family. The maximum lodscore was 6.37 at 0 recombination for DXS52 and 5.99 at 0 recombination for DXS305. Crossovers were demonstrated between the disorder and DXS455. Clinical and linkage data from this family further support the hypothesis that the MASA syndrome and X-linked hydrocephalus are allelic disorders.

Prenatal diagnosis of Smith-Lemli-Opitz syndrome, type II.

Smith-Lemli-Opitz syndrome, type II (SLOS-II) is a severe autosomal recessive disorder characterized by a distinctive face, unusual cleft palate, postaxial polydactyly, congenital heart defects, renal anomalies, and male pseudohermaphroditism. We present the first report of prenatal diagnosis of SLOS-II, as well as an additional report of prenatal detection of multiple anomalies, in which a positive diagnosis of SLOS II was made postnatally. In neither case was the pregnancy known prospectively to be at risk for SLOS-II. In the former case, targeted sonographic examination at 31 weeks of gestation showed intrauterine growth retardation, atrioventricular septal defect, mesomelic shortening of the arms, small kidneys, overlapping fingers, and female external genitalia; a 46,XY chromosome constitution had been ascertained previously. A provisional diagnosis of SLOS-II was made prenatally. In the latter case, targeted sonographic examination at 18 weeks of gestation showed severe oligohydramnios, atrioventricular septal defect, and Dandy-Walker malformation. The kidneys and bladder were not visualized. The chromosome constitution was 46,XX. The diagnosis of SLOS-II was made postnatally. In both cases, additional findings compatible with SLOS-II were noted postnatally. Prenatal detection of congenital heart defects and renal abnormalities, in combination with certain additional findings (most notably, female external genitalia in the presence of a 46,XY karyotype, polydactyly, disproportionately short limbs, or intrauterine growth retardation) and a normal karyotype, suggests the diagnosis of SLOS-II, and warrants further investigation.

Provisionally unique autosomal recessive chondrodysplasia punctata syndrome.

Stippled epiphyses occur in several monogenic, teratogenic, or aneuploidy syndromes. We describe two sibs with a provisionally unique chondrodysplasia punctata syndrome, who have, in addition to stippled epiphyses, minor facial anomalies, short stature, and ocular colobomata. Inheritance of this condition is likely autosomal recessive.

Localization of the translocation breakpoint in a female with Menkes syndrome to Xq13.2-q13.3 proximal to PGK-1.

Menkes syndrome is a rare X-linked recessive disorder characterized by an inability to metabolize copper. A female patient with both this disease and an X; autosome translocation with karyotype 46,X,t(X;2)(q13;q32.2) has previously been described. The translocation breakpoint in Xq13 coincides with a previous assignment of the Menkes gene at Xq13 by linkage data in humans and by analogy to the mottled mutations which are models for Menkes disease in the mouse. Therefore, this translocation probably interrupts the gene for Menkes syndrome in band Xq13. We describe here experiments to precisely map the translocation breakpoint within this chromosomal band. We have established a lymphoblastoid cell line from this patient and have used it to isolate the der(2) translocation chromosome (2pter----2q32::Xq13----Xqter) in human/hamster somatic cell hybrids. Southern blot analyses using a number of probes specific for chromosomes X and 2 have been studied to define precisely the location of the translocation breakpoint. Our results show that the breakpoint in this patient--and, therefore, likely the Menkes gene--maps to a small subregion of band Xq13.2-q13.3 proximal to the PGK1 locus and distal to all other Xq13 loci tested.

DiGeorge anomaly in an infant with deletion of chromosome 22 and dup(9p) due to adjacent type II disjunction.

A term white girl presented with low birth weight, minor anomalies, and congenital heart defects. The infant had microcephaly, upslanting palpebral fissures, prominent nasal bridge, short philtrum, thin upper lip vermilion, down-turned corners of the mouth, receding mandible, and short broad neck. The hands showed proximal placement of the thumbs, bilateral clinodactyly of the index finger, and bilateral transverse crease. Both hands were clenched, with the index finger overlapping the third finger and the fifth finger overlapping the fourth. There was also talipes calcaneo-valgus, bilateral dorsiflexion of the metatarsophalangeal joints, flexion of the interphalangeal joints, and hypoplasia of all nails. The patient's karyotype was 46,XX,-22, + der(9)t(9;22)(q21.13;q12.1)mat; the mother had the balanced translocation 46,XX,t(9;22)(9pter----9q21.13::22q12.1----22qter++ +;22pter---- 22q12.1::9q21.3----9qter). The infant died at age 10 days, and the autopsy showed absent thyroid isthmus and rudimentary thymus, with one small ectopic parathyroid attached to it. The lungs were hypoplastic, with abnormal lobation. The cardiac anomalies included truncus arteriosus, truncal valve stenosis, single carotid trunk, subclavian arteries arising from the distal part of the aortic arch, atrial and ventricular septal defects, right ventricular hypertrophy, and a hypoplastic left pulmonary artery. Also, multiple small accessory spleens were present in addition to a normal-sized spleen. This case combines features associated with DiGeorge anomaly and dup(9p). The chromosome abnormality in this patient appears to have arisen in a maternal germ cell due to adjacent type II disjunction.

Two siblings with Tel Hashomer camptodactyly and mitral valve prolapse.

A brother and sister with Tel Hashomer camptodactyly and mitral valve prolapse are described. Mitral valve prolapse is heterogenous, but appears to occur more frequently in individuals with connective tissue disorders. The presence of mitral valve prolapse as a component manifestation of Tel Hashomer camptodactyly suggests that abnormal connective tissue is a pleiotropic effect of the mutant allele.

Renal tubular dysgenesis: delayed onset of oligohydramnios.

Two premature sibs had Potter sequence and died of respiratory failure within the first day. Ultrasonography at 26 weeks during the earlier of the two pregnancies showed complete absence of amniotic fluid, and the urinary bladder was not visualized. Ultrasound examinations during the second pregnancy showed adequate amniotic fluid at 16 and 20 weeks, with a subsequent reduction in fluid volume. Two older sibs had also died of respiratory failure shortly after birth. Postmortem histopathologic studies showed all four sibs to have severely deficient renal tubular development. However, the presence of numerous glomeruli indicated prolific nephrogenesis. Most of the tubules in sections of cortex had the lectin-binding and immunohistochemical characteristics of collecting ducts; proximal tubules were not identified by lectin-binding. Electron-microscopic examination showed a general absence of differentiated characteristics in cortical tubular epithelium, except that rare tubules contained rudimentary proximal tubular brush borders. Three of the sibs were boys, one a girl. The three children that were studied had normal chromosomes. Two unaffected sibs are alive and well. Neither parent has any clinical evidence of renal disease. These studies support the interpretation that renal tubular dysgenesis is autosomal recessive with pleiotropy. However, the relatively late appearance of oligohydramnios makes early diagnosis difficult, even when the condition is suspected.

Acute lymphoblastic leukemia with a unique rearrangement between chromosomes 4 and 11.

A case of pre-B cell acute lymphoblastic leukemia (pre-B ALL) with a dir ins(11;4)(q23;q21q31) chromosome rearrangement is presented. The patient's clinical findings and history were similar to those described for the t(4;11)(q21;q23) subgroup of childhood ALL. These findings suggest that the interfacing of the distal breakpoint at band 4q21 to the proximal breakpoint of band 11q23 represents the primary cytogenetic change observed in this subgroup of ALL.