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J Allanson

Publications and source records attributed to J Allanson.

33 records · Page 2Linked to original sources
PubMed1992

Ultrasonographic measurements of fetal ear.

OBJECTIVE: To establish nomograms of fetal ear measurements. Newborns with trisomies have smaller ears than the normal population. This observation led us to believe that ear measurements might be useful in the antenatal prediction of fetuses with abnormal karyotypes. METHODS: Fetal ear length and width were obtained ultrasonographically in 124 normal singleton pregnancies between 18-42 weeks' gestation. Regression analyses were used to create the nomograms. RESULTS: Linear relationships were found between ear length and width and gestational age (r = 0.956 and 0.898, respectively). In addition, there were significant correlations between ear measurements and biparietal diameter, head circumference, abdominal circumference, and femur length. The ear width-length ratio and the biparietal diameter-ear length ratio were independent of gestational age. CONCLUSION: These normative data may be helpful in the antenatal prediction of chromosomal abnormalities.

Down Syndrome↗
PubMed1989

Not all chromosome imbalance resulting from the 11q;22q translocation is due to 3:1 segregation in first meiosis.

The constitutional translocation between chromosomes 11 and 22 [t(11;22)(q23.3;q11.2)] is one of the best known rearrangements in the human genome. Hitherto only one type of unbalanced karyotype, namely 47,XX or XY, +der(22) t(11;22)(q23.3;q11.2) was found among offspring of the translocation carriers. This result is the product of a 3:1 segregation at meiosis. We report an alternative unbalanced karyotype. The proband's karyotype is 47,XY,t(11;22)(q23.3;q11.2), +der(22)t(11;22)(q23.3;q11.2)pat. This finding cannot be due to nondisjunction in first meiosis of the translocation carrier.

Chromosome Banding↗
PubMed1989

Abnormal chromosome complement resulting from a familial inversion of chromosome 2.

It has been suggested that pericentric inversions of chromosome 2 increase the risk for spontaneous abortion but do not increase the risk for unbalanced recombinant offspring. We report our experience of a familial pericentric inversion of chromosome 2 resulting in two unbalanced recombinant offspring. Both subjects have 46,XX,rec(2),dup q,inv(2)(p25q35).

Abnormalities, Multiple↗
PubMed1989

Severe Silver-Russell syndrome.

Three children are described with severe Silver-Russell syndrome. Major medical problems occurred in the first two years of life in all three. Silver-Russell syndrome should be considered in the differential diagnosis of children with severe pre- and postnatal growth deficiency.

Child, Preschool↗
PubMed1989

Familial translocation t(9;16).

We report a female with a deletion of 9p and concomitant duplication of 16q [46,XX,-9,+der(9),t(9;16)(p24;q13)]. Parental chromosome analysis showed a balanced maternal translocation [46,XX,t(9;16)(p24;q13)]. Three other cases of translocations involving chromosomes 9 and 16 have been reported, one of them with identical breakpoints. A review of published reports of deletion 9p and duplication 16q is presented, and a comparison is made with previously described cases.

Abnormalities, Multiple↗
PubMed1988

Chromosome subband 17p11.2 deletion: a minute deletion syndrome.

Interstitial deletion of the short arm of chromosome 17 was detected in three unrelated patients with mental retardation and multiple congenital malformations. These patients were identified at a single centre over a six month period suggesting that del(17) (p11.2p11.2) is not a rare constitutional chromosome rearrangement. Comparison of the phenotypic features in a total of 19 patients with del(17)(p11.2p11.2) shows a consistent clinical phenotype with moderate to severe mental retardation, microbrachycelphaly, prominent forehead, broad face, flat midface, prognathism, short, broad hands, and behavioural anomalies such as self-mutilation. The sex ratio is unremarkable, parental ages are normal, and survival is usually unimpaired. Chromosome resolution of at least 500 bands appears necessary to detect this deletion.

Abnormalities, Multiple↗
PubMed1987

Smith-Lemli-Opitz syndrome-type II: multiple congenital anomalies with male pseudohermaphroditism and frequent early lethality.

In 1964, Smith et al described a syndrome of microcephaly, growth and mental retardation, unusual facial appearance, syndactyly of toes 2 and 3, and genital abnormalities. Major structural malformations and early death have been uncommon in the many subsequent literature reports. We report on 19 infants with a phenotype we propose to call Smith-Lemli-Opitz syndrome (SLOS)-Type II, in which major structural abnormalities, male pseudohermaphroditism, and early lethality are common. Of these 19 patients, 18 had postaxial hexadactyly, 16 had congenital heart defect, 13 had cleft palate, and 10 had cataracts. Unusual findings seen in these patients at autopsy included Hirschsprung "disease" in five patients, unilobated lungs in six, large adrenals in four, and pancreatic islet cell hyperplasia in three. Comparison of our cases to 19 similar literature cases suggests the existence of a distinct phenotype that may be separate from SLOS as originally described. It is also inherited as an autosomal recessive, as documented by occurrence in one pair of sibs in this study and recurrence in three reported families.

Abnormalities, Multiple↗
PubMed1986

Congenital cutis laxa with retardation of growth and motor development: a recessive disorder of connective tissue with male lethality.

A syndrome of cutis laxa, ligamentous laxity and delayed motor development has been reported in 13 children. All are girls. Four are from Saudi Arabia. Another Saudi Arabian girl, the product of a consanguineous union, is described with intrauterine growth retardation, delayed closure of the anterior fontanel, slow motor development, cutis laxa and ligamentous laxity. The syndrome appears to be an autosomal recessive disorder of connective tissue, with male lethality.

Consanguinity↗
PubMedDate not supplied

Prenatal diagnosis in congenital contractural arachnodactyly.

Congenital contractural arachnodactyly (CCA) is a heritable connective tissue disorder caused by defects in the gene encoding fibrillin-2 (FBN2). People with CCA typically have a marfanoid habitus, flexion contractures, severe kyphoscoliosis, abnormal pinnae, and muscular hypoplasia. Because of the relative infrequency of the syndrome and its generally mild to moderate severity, prenatal diagnosis had not previously been sought. Here we report prenatal diagnosis in a family with CCA. Because the course of the disease in the proband was rather severe, she had requested genetic counseling as early as age 17. She delayed childbearing until prenatal diagnosis for CCA became possible. This decision was supported by her mother and later her husband. Because she shared the same genotype with her husband, genetic linkage analysis of this family did not alter the a priori 50% risk of having an affected child. The possibility of unambiguously ascertaining the affected status of a fetus homozygous for the tested FBN2 marker was sufficient for the family to pursue prenatal diagnosis. This case strongly points to the importance of informed decisions now that genetic testing is becoming commonplace.

Adult↗