Paucity of intrahepatic bile ducts, solitary kidney and atrophic pancreas with diabetes mellitus: atypical Alagille syndrome?

A child with the tentative diagnosis of Alagille syndrome is reported. Additional renal abnormalities are unilateral kidney agenesis and a kidney with subcortical cysts with decreased function. At the age of 5 years, insulin-dependent diabetes mellitus developed, with the pancreas being atrophic and negative pancreatic islet cell antibodies.

CONCLUSION

This observation extends the picture of Alagille syndrome and suggests an overlap with renal-hepatic-pancreatic dysplasia (Ivemark syndrome).

Ichthyosis-characteristic appearance-mental retardation syndrome with distinct histological skin abnormalities

In this report, we describe a 2.5-year-old severely mentally retarded boy with peculiar appearance and generalized ichthyosis, born to consanguineous Turkish parents. The histological finding in the skin biopsy of unusually large oval keratohyalin granules in the granular cells is unique, and hitherto has not been reported in other ichthyosis-mental retardation syndromes.

Alopecia-mental retardation syndrome associated with convulsions and hypergonadotropic hypogonadism

We report two brothers with congenital total alopecia, mental retardation, childhood convulsions and hypergonadotropic hypogonadism. This association has not previously been reported and probably represents a new autosomal recessive condition.

Isolation of cosmids corresponding to the chromosome breakpoints of a de novo autosomal translocation, t(6;19)(p21;q13.1), in a patient with multicystic renal dysplasia

Hydronephrosis caused by pelvi-ureteric junction obstruction (PUJO) is a frequent urological malformation assumed to result from a deficient development of the ureteric bud. The exact etiology of pelvi-ureteric junction stenosis is unknown, but there is convincing evidence for a genetic cause, with linkage analysis predicting a hereditary hydronephrosis locus on chromosome 6p. We encountered a patient with a de novo autosomal t(6;19)(p21;q13.1) and attendant bilateral multicystic renal dysplasia (MRD), bilateral PUJO resulting in massive hydronephrosis, and an associated von Mayer-Rokitansky-Kuster disorder. On the basis of the presumption that in this patient the putative hydronephrosis gene might be disrupted by the translocation, we sought to isolate DNA from the breakpoint regions as the initial step in a strategy to identify genes affected by the t(6; 19). Using sequential rounds of fluorescence in situ hybridization (FISH) with cosmids selected from a detailed integrated map of the long arm of chromosome 19, we have identified a cosmid clone that spans the breakpoint. The position of the breakpoint was further localized by Southern blot analysis. Using a vectorette PCR approach, rearranged DNA fragments were isolated and, by comparative nucleotide sequence analysis, these were shown to contain ectopic sequences. A cosmid clone containing these ectopic sequences was isolated and shown by CASH (chromosome assignment using somatic cell hybrids) and FISH (fluorescence in situ hybridization) analysis to map to the short arm of chromosome 6 and to span the breakpoint found in the MRD patient. The isolated cosmid clones are useful reagents for analysis of other MRD patients and for the search for genes at or flanking the breakpoints.

Diaphragmatic hernia in Denys-Drash syndrome

We report on a newborn infant with male pseudohermaphroditism and glomerular lesions (Denys-Drash syndrome) but without Wilms tumor. A constitutional heterozygous mutation in the WT1 gene (366Arg to His) was identified. In addition the child had a large diaphragmatic hernia, so far not described in Denys-Drash syndrome. The expression of the WT1 gene in pleural and abdominal mesothelium and the occurrence of diaphragmatic hernia in transgenic mice with a homozygous WT1 deletion strongly suggests that the diaphragmatic hernia in this patient is part of the malformation pattern caused by WT1 mutations.

Severe alport phenotype in a woman with two missense mutations in the same COL4A5 gene and preponderant inactivation of the X chromosome carrying the normal allele

The X-linked form of Alport disease, caused by mutations in the COL4A5 or the COL4A6 gene, usually leads to terminal renal failure in males, while affected females have a more variable and moderate phenotype. We detected in a female patient, with a severe Alport phenotype, two new missense mutations. One mutation (G289V) occurred in exon 15 and converted a glycine in a collagenous domain of COL4A5 to a valine. The second mutation, located in exon 46, substituted a cysteine proximal to the NC1 domain of COL4A5 for an arginine. In white blood cells and kidney both mutations were present on > 90% of the mRNA, while at the genomic level the patient was heterozygous for both mutations. The two mutations therefore occurred in the same COL4A5 allele. No mutation was found in the COL4A5 promoter region by sequencing nor was a major rearrangement of the normal allele detected. A skewed pattern of X inactivation was demonstrated in DNA isolated from the patient's kidney and white blood cells: > 90% of the X chromosomes with the normal COL4A5 allele was inactivated. It is suggested that this skewed inactivation pattern is responsible for the absence of detectable normal COL4A5 mRNA and hence the severe phenotype in this woman.

Growth hormone deficiency and premature thelarche in a female infant with kabuki makeup syndrome

We report on a girl with the kabuki makeup syndrome, including short stature, premature thelarche and partial growth hormone deficiency of hypothalamic origin, without stalk interruption. Treatment with recombinant human growth hormone resulted in an increase of annualized growth velocity from 3.6 to 11.2 cm. The kabuki makeup syndrome may be associated with hypothalamopituitary dysfunction.

Asplenia syndrome and isolated total anomalous pulmonary venous connection in siblings

We report on a family with asplenia syndrome in one and total anomalous pulmonary venous connection (TAPVC) in the other sib. Both conditions are rare, may have a genetic cause and belong to a spectrum of laterality disorders. This suggests that both asplenia syndrome and TAPVC in this family are the clinical expression of a single genetic disorder.

Opposite effects of growth hormone and estrogens on the pregnancy zone protein serum levels in children and adolescents

Serum levels of pregnancy zone protein were measured in children with growth hormone deficiency and in girls with Turner syndrome, before and during treatment with recombinant human growth hormone and in healthy controls. The pregnancy zone protein serum levels in growth hormone deficiency patients before treatment were significantly higher than in controls (median value 2420 micrograms/l vs 434 micrograms/l; p < or = 0.001). In Turner syndrome patients they were within the normal range. The administration of rhGH to both growth hormone deficiency and Turner syndrome patients resulted in a significant decrease in the serum pregnancy zone protein levels by approximately 50%. The addition of 50 ng.kg-1.d-1 ethinylestradiol to the growth hormone treatment in Turner syndrome patients led to an increase in pregnancy zone protein concentrations in four out of five patients. Elevated pregnancy zone protein levels were also found in two children with growth hormone resistance (Laron type dwarfism). In one patient with placental growth hormone deficiency, pregnancy zone protein serum levels during pregnancy were within the normal range. These results suggest that the serum pregnancy zone protein levels are down-regulated by growth hormone.

Wiedemann-Beckwith syndrome and chromosomal duplication 4q/deficiency 18p

In this report we present a female newborn with Wiedemann-Beckwith syndrome and duplication 4q/deficiency 18p as the result of an unbalanced paternal 4q/18p translocation: karyotype: 46,XY,t(4;18)(q34.2;p11.32). The different mechanisms resulting in prenatal overgrowth and Wiedemann-Beckwith syndrome phenotype are reviewed. The suggestion is made that contiguous gene duplications/deletions other than those located in the 11p15 region may exist.

Structure of the human alpha-2 macroglobulin gene and its promotor

The human alpha 2-macroglobulin gene was isolated in five overlapping clones. The gene spans approx. 48 kb and consists of 36 exons, from 21 to 229 bp in size and with consensus splice sites. Intron sizes range from 145 bp to 7.5 kb. The alpha 2M gene is a single copy gene in the human genome. A sequence polymorphism within the bait domain, coding for an Arg to His substitution within the primary cleavage site for trypsin, was identified in 1 of 132 individuals tested so far. Three transcription initiation sites have been identified in liver by primer extension and RNase protection assays. The most proximal, major site (+1) is preceded by a TATA-like structure (ATAAA) at -26 bp. Only 2 mRNA species were found in uterus and in cultured lung fibroblasts, while alpha 2M is not expressed to a detectable level in skin fibroblasts. The far distal transcription initiation site which is preceded by an intact TATA box and a potential HP-1 binding site is thus specific for liver.

Primary structure of pregnancy zone protein. Molecular cloning of a full-length PZP cDNA clone by the polymerase chain reaction

A full-length cDNA clone of the human pregnancy zone protein (PZP) was cloned from the hepatocellular carcinoma cell line Hep3B. Based on the exon sequences of the PZP gene (Devriendt et al. (1989) Gene 81, 325-334; Marynen et al., unpublished data), primer pairs were designed to amplify six overlapping fragments of the PZP cDNA. The obtained cDNA is 4609 bp long and contains an open reading frame coding for 1482 amino acids, including a signal peptide of 25 amino acid residues. Comparison with the published partial PZP amino acid sequence (Sottrup-Jensen et al. (1984) Proc. Natl. Acad. Sci. USA 81, 7353-7357) and the PZP genomic sequences confirmed the identity as a PZP cDNA. 71% of the corresponding amino acid residues in PZP and human alpha 2-macroglobulin (alpha 2M) are identical and all cysteine residues are conserved. A typical internal thiol ester site and a bait domain were identified. A Pro/Thr polymorphism was identified at amino acid position 1180, and an A/G nucleotide polymorphism at bp 4097.

Chromosome mapping using polymerase chain reaction on somatic cell hybrids

DNA polymerase chain reaction (PCR) was used to detect specific human sequences in human-mouse somatic hybrids. As compared with classic Southern blotting, this technique appeared to be more sensitive and less time-consuming for gene mapping.

A genetic polymorphism in a functional domain of human pregnancy zone protein: the bait region. Genomic structure of the bait domains of human pregnancy zone protein and alpha 2 macroglobulin

Genomic clones containing the exons coding for the bait domain of human pregnancy zone protein and alpha 2 macroglobulin were isolated and fragments containing the bait exons were sequenced. It is shown that the bait domains of both alpha 2 macroglobulin and pregnancy zone protein are encoded by two exons, with conserved exon/intron boundaries. A genetic polymorphism showing either a Met or a Val residue as the sixth amino acid of the pregnancy zone protein bait domain was detected with the rare Met allele showing a gene frequency of 0.065.

Molecular analysis of the isochromosome 12P in the Pallister-Killian syndrome. Construction of a mouse-human hybrid cell line containing an i(12p) as the sole human chromosome

An iso 12p chromosome from a patient with Pallister-Killian syndrome was successfully transferred into a mouse background by microcell-mediated chromosome transfer. The presence of the i(12p) chromosome was confirmed by karyotyping and by Southern blotting using five 12p and seven 12q probes. The isochromosome nature of the marker chromosome was confirmed by co-hydridization of a 12p probe with a 12q and an 8q probe. This cell line should be a valuable tool for physical mapping of 12p-derived DNA fragments; at the same time, it confirms the identity of the extra chromosome in the Pallister-Killian syndrome as i(12p).

A cluster of alpha 2-macroglobulin-related genes (alpha 2 M) on human chromosome 12p: cloning of the pregnancy-zone protein gene and an alpha 2M pseudogene

The characterization of two alpha 2-macroglobulin (alpha 2M)-related genomic clones, isolated from two human genomic libraries by use of alpha 2M cDNA [Kan et al., Proc. Natl. Acad. Sci. USA 82 (1985) 2282-2286] as a probe, is reported. Sequence comparison of the clone EPZP6 with the human alpha 2M cDNA revealed the presence of five exons with the proper splice signals. Alignment of the corresponding amino acid (aa) sequence of these exons with the published partial pregnancy-zone protein (PZP) aa sequence (Sottrup-Jensen et al., Proc. Natl. Acad. Sci. USA 81 (1984) 7353-7357] showed a perfect match, thereby identifying EPZP6 as a PZP genomic clone. The clone MPAM16 showed a considerable degree of sequence conservation when compared to the human alpha 2M cDNA sequence, and several putative exons were identified. However, a frame-shift mutation leading to a premature stop codon was found in the coding sequence, classifying this gene as an alpha 2M pseudogene. Human alpha 2M, PZP and the related pseudogene were mapped to the human chromosome 12p12-13, with the help of gene-specific probes and in situ hybridization. This result was confirmed in Southern-blot experiments with DNA from a human-Ltk- mouse somatic-cell hybrid containing only a human isochromosome 12p in a mouse background.