Autosomal phosphogluconic dehydrogenase polymorphism in the cat (Felis catus L.).

Three patterns of 6-phosphogluconic dehydrogenase activity were obtained by starch-gel electrophoresis of blood from domestic cats. Genetic analysis indicates control of these patterns by a pair of alleles at an autosomal locus. Presence of three enzymatically active bands in heterozygotes and of single bands in homozygotes is compatible with at least a dimeric structure for the enzyme.

Nonrandomness of translocations in man: preferential entry of chromosomes into 13-15-21 translocations.

Lymphocytes from 20 individuals with Down's syndrome due to 13-15/21 centric-fusion translocations were studied by autoradiography after continuous late labeling with tritiated thymidine. In no case was chromosome 13 involved; chromosome 14 was involved in 18 cases, and chromosome 15 in two cases. These results are similar to those from 13 previously studied cases and indicate that the entry of chromosomes 13-15 into translocations is nonrandom. This nonrandomness is not a simple function of chromosome size or shape, since chromosomes 13-15 are acrocentrics of similar size.

Worldwide experience in newborn screening for classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

The need for a reliable screening test for classical congenital adrenal hyperplasia prompted development of newborn screening programs. Worldwide incidence of classical congenital adrenal hyperplasia in this report was taken from newborn screening programs in France, Italy, Japan, New Zealand, Scotland, and the United States. Two populations in which the occurrence of congenital adrenal hyperplasia among live births has been reported with greater than usual frequency are the Yupik Eskimos of southwestern Alaska (1:282) and the people of La Reunion, France (1:2,141). Aside from these populations, 1,093,310 newborns were screened between 1980 and 1988, of whom 77 had congenital adrenal hyperplasia. Thus, worldwide incidence of this disorder was estimated at 1:14,199 live births for homozygous patients, 1:60 for heterozygous subjects, with a gene frequency of 0.0083. Incidence of congenital adrenal hyperplasia among whites was estimated to be 1:11,909 (41:488,279) for homozygous patients, 1:55 for heterozygous subjects with a gene frequency of 0.0091. Incidence for the salt-wasting form of congenital adrenal hyperplasia was 1:18,850 (58:1,093,310) compared with 1:57,543 (19:1,093,310) for congenital adrenal hyperplasia in the simple virilizing form. Thus, salt-wasting congenital adrenal hyperplasia was three times more common than simple virilizing congenital adrenal hyperplasia. Estimated incidence of congenital adrenal hyperplasia in white populations in Italy and France (1:10,866) was higher than in Scotland (1:17,098), New Zealand (1:14,500). The incidence in an Asian population (Japan) (1:15,800) did not differ significantly from that of the white population. In four of five populations, overall incidence was higher than previously reported, as was the frequency of the salt-wasting form (75% v 50% to 66%), suggesting improved case detection by newborn screening.(ABSTRACT TRUNCATED AT 250 WORDS)

Deletion of chromosome 15 (q11-13) in a Prader-Labhart-Willi syndrome clinic population.

Deletion of the long arm of chromosome 15 has recently been reported in a number of patients with the Prader-Labhart-Willi syndrome who were studied with prometaphase banding. We performed cytogenetic analysis on 12 patients with this disorder in whom the clinical diagnosis was certain. A specific cytogenetic anomaly, del(15q11-13) was found in all of the 12 patients. In nine of the 12, the deletion was noted in all cells examined; in two, there was mosaicism, some cells having the deletion and others being normal; one patient had a 7;15 translocation. No clinical differences were evident between individuals with mosaicism for the translocation and those with the typical deletion in all cells examined. The finding that all of our patients with Prader-Labhart-Willi syndrome have a cytogenetic anomaly, with some patients having mosaicism, distinguishes the results of this study from those of previous reports. Prometaphase chromosome analysis is recommended in all individuals clinically suspected of having Prader-Labhart-Willi syndrome and should be considered in hypotonic infants without a specific diagnosis.

Partial deletion of the long arm of chromosome 11 [del(11)(q23.3----qter)] with abnormal white matter.

A patient with partial deletion of the long arm of chromosome 11[del(11)(q23.3----qter)] had macrocephalic trigonocephaly, growth and mental retardation, congenital heart defect, and characteristic facial appearance familiar to that of 33 other reported patients with this deletion. Computed tomography (CT) and magnetic resonance imaging of this infant's brain demonstrated abnormality of the supratentorial white matter. This may represent either deficiency or delay in myelination or possibly a demyelination process. No abnormalities in white matter were described in seven of 33 previously reported patients whose brains were examined by ultrasound, CT, or autopsy.

Familial insertional translocation of a portion of 3q into 11q resulting in duplication and deletion of region 3q22.1 leads to q24 in different offspring.

The use of elongated prophase and prometaphase chromosome preparations has allowed detection of an insertion of a small segment of 3q into 11q in a kindred with 4 balanced carriers and 8 unbalanced offspring. Those with partial 3q deletion have a true multiple congenital anomalies/mental retardation (MCA/MR) syndrome with an appearance suggestive of the Schwartz-Jampel syndrome.

Defective antibody response to bacteriophage phichi 174 in Down syndrome.

Antibody responses to bacteriophage phichi 174 were studied in 17 institutionalized patients with trisomy 21 and in six mentally retarded control patients with normal karyotype. Primary antibody response was significantly impaired in 11 of the 17 patients. Secondary immune response was normal in one, moderately impaired in seven, and very low in nine patients. Tertiary immunization further differentiated the two groups: those with moderately impaired secondary immune responses developed normal serum titers of predominantly IgG antibody; patients with low secondary immune responses had extemely impaired tertiary immune responses consisting mainly of serum IgM antibody.

Chromosome 13 long arm interstitial deletion associated with features of Noonan phenotype.

A 22-year-old Caucasian mildly retarded male presented with facial features of high nasal bridge, prominent supraorbital ridges, some malar hypoplasia, prognathism, short philtrum, and prominent full lips associated with shortness of stature, nuchal webbing, and esotropia. His cardiac exam and genital development were normal. The diagnosis of Noonan syndrome had been previously entertained. A chromosome analysis revealed an interstitial deletion of a chromosome 13 at (q21.32q22.3).

Molecular detection of a translocation (Y;15) in a 45,X male.

A 45,X male individual was shown to have a translocation of Y-chromosome material to the short arm or proximal long arm of chromosome 15. This translocation was detected by genomic DNA blotting and in situ hybridization with Y-chromosome-specific DNA probes.

Deletion mapping of H-Y antigen to the long arm of the human Y chromosome.

A gene encoding or controlling the expression of the H-Y transplantation antigen was previously mapped to the human Y chromosome. We now report the sublocalization of this gene on the long arm of the human Y chromosome. Eight patients with Y-chromosomal abnormalities were examined with a series of existing and new DNA markers for the Y chromosome. The resulting deletion map was correlated with H-Y antigen expression. We conclude that the H-Y antigen gene maps to a portion of deletion interval 6 that is identified by specific DNA markers.