Search PubMed⌕ Search

Biomedical subjects

D Donnai

Publications and source records attributed to D Donnai.

At least 91 records · Page 5Linked to original sources
PubMed1994

The influence of genetic counselling in the era of DNA testing on knowledge, reproductive intentions and psychological wellbeing.

Subjects of reproductive age at risk of having an affected child with a severe single gene disorder such as Duchenne muscular dystrophy (DMD) or cystic fibrosis (CF) were surveyed to ascertain: their views on genetic counselling and antenatal testing; their knowledge of their risk of having an affected child; and their psychological wellbeing. Questionnaires were posted to 209 individuals at 130 addresses; a 65% response rate was achieved. The majority of those surveyed were under 40 years of age (91%), half of them had received genetic counselling only once and for 47% the first encounter was after the diagnosis of their affected child. Most patients expressed their intention to use prenatal testing. However, less than 50% of those counselled knew their risk of having an affected child. Knowledge of risk was associated with the type of disease in the family (p < 0.001) (inheritance of DMD was poorly understood by relevant subjects) and was positively associated with the participant's level of education (p < 0.05). We did not detect a significant association between the number of intended children and the risk of having an affected child. In terms of family relations, genetic counselling appears to be beneficial for the nuclear family, the couple and their children, but some counselees reported a deterioration in relations with other relatives. The results indicate that couples at risk of having a child with a severe genetic disorder value the counselling provided, but many of them do not remember important facts in relation to their risk status.

Adolescent↗
PubMed1994

Ohdo-like blepharophimosis syndrome with distinctive facies, neonatal hypotonia, mental retardation and hypoplastic teeth.

We report four children with unusual facial features including severe blepharophimosis, ptosis, and a distinctive nose with a broad flat tip and a depressed bridge. All four patients were markedly hypotonic and had severe feeding difficulties and developmental delay. Two had congenital heart defects and all three who survived had hypoplastic teeth. Both of the male patients had cryptorchidism. These four children have a distinctive syndrome which is similar to that reported by Biesecker (J Med Genet (1991) 28: 131-134).

Abnormalities, Multiple↗
PubMed1993

Brachmann-de Lange syndrome. Delineation of the clinical phenotype.

A total of 31 cases previously diagnosed as having Brachmann-de Lange syndrome were ascertained and examined, of which 11 were thought to have been misdiagnosed. Of those correctly diagnosed, there appeared to be a phenotypic dichotomy with classical and mild cases. Those facial findings of greatest diagnostic value were the combination of the characteristic eyebrows, long philtrum, thin lips and crescent-shaped mouth. The characteristic eyebrows were neat, well defined and arched as though they had been pencilled. This combination of anomalies was absent in postpubertal males but not in postpubertal females. Facial abnormalities most likely to lead to incorrect use of the eponym were hypertrichosis, synophrys, and bushy eyebrows.

Adolescent↗
PubMed1993

Diaphragmatic hernia, exomphalos, absent corpus callosum, hypertelorism, myopia, and sensorineural deafness: a newly recognized autosomal recessive disorder?

We describe unrelated male and female patients with an identical syndrome of diaphragmatic hernia, exomphalos, hypertelorism, agenesis of the corpus callosum, severe sensorineural deafness, and severe myopia. One child had an iris coloboma. After the birth of the first affected child in each family subsequent pregnancies were monitored with ultrasound scan and a further affected fetus was identified in both families. We conclude that this constellation of anomalies represents a distinct, previously unreported syndrome with likely autosomal recessive inheritance.

Abnormalities, Multiple↗
PubMed1993

True telomeric translocation in a baby with the Prader-Willi phenotype.

We report on a baby with a nonreciprocal de novo unbalanced translocation between chromosomes 12 and 15. Her karyotype was 45,XX, -12, -15, +der(12)t(12;15)(pter-->qter::q13-->qter). The paternal origin of the 15q11-13 region was shown by DNA marker studies and, consistent with this, the baby had the Prader-Willi (PWS) phenotype. The breakpoint on 12q was distal to D12S11 (lambda MS43) which maps to 12q24.3-qter. Fluorescent in situ hybridization using the oligonucleotides (TTAGGG)7 and (AATCCC)7 showed that the 12q telomere was still present within the translocated chromosome. Thus, the translocation was within or onto the end of the telomere of 12q. This unusual translocation is further evidence of an unexplained instability of the 15q11-13 region.

Chromosome Banding↗
PubMed1993

NICHD conference. Robertsonian translocations: clues to imprinting.

Robertsonian translocations, occurring with a frequency of about 1 in 10,000 livebirths, may be an important cause of uniparental disomy as demonstrated for 13/15, 13/14, 14/14, and 22/22 translocations. Dysmorphogenesis and/or mental retardation provide clinical clues for uniparental disomy in apparently balanced offspring of translocation carriers. Research strategies for assessing frequency and implications of uniparental disomy in translocation carriers include a genetic register approach, study of abortuses from balanced translocation carriers, and parent-of-origin studies on de novo homologous Robertsonian translocations.

Chromosomes, Human, Pair 13↗
PubMed1993

Refining the genetic location of the gene for X linked hydrocephalus within Xq28.

The most common inherited form of hydrocephalus, X linked hydrocephalus (HSAS), is characterised by mental retardation, adducted thumbs, and spastic paraplegia. Genetic analysis has mapped the locus for HSAS to subchromosomal band Xq28 within a region of approximately 2 megabases of DNA. In order to refine the location of the disease gene we have conducted genetic linkage analysis with Xq28 marker loci in four additional HSAS families. A lod score of 4.26 with polymorphic marker DXS52 (St14) confirms the linkage of HSAS to Xq28. Identification of a recombination event between the HSAS gene and Xq28 loci F8C and DXS605 (2-19) reduces the size of the interval likely to contain the disease locus to about 1.5 megabases, the distance between DXS605 and DXS52. The locus for neural cell adhesion molecule, L1CAM, maps within this interval and therefore represents a candidate gene for HSAS.

Adolescent↗
PubMed1993

Neurofibromatosis type 1 (NF1): knowledge, experience, and reproductive decisions of affected patients and families.

Eighty-one subjects (56 affected patients and 25 parents of isolated affected cases) from 63 families with neurofibromatosis type 1 (NF1) on the North Western Regional Genetic Family Register (NWRGFR) were interviewed. Patients were interviewed either before (n = 26) or after (n = 55) genetic counselling. In the group as a whole, knowledge of the clinical features and the genetic aspects of the condition was poor (mean score 7 within the range of 0 to 18). The following factors were significantly associated with higher knowledge: (1) genetic counselling, (2) higher social class, (3) child with NF1, (4) when NF1 had influenced reproductive decisions, (5) young age at diagnosis, and (6) member of a patient support group. The majority of the affected subjects perceived themselves to be more severely affected than by medical classification, with persons who had been diagnosed later in life, had a child with NF1, or who were concerned about the cosmetic aspects of the disease perceiving themselves to be more severely affected. Assessment of the psychosocial effects of NF1 at different stages of life showed that 63% of affected subjects experienced difficulties at school and 48% said that the condition, particularly cosmetic aspects, caused anxiety during adolescence (n = 54). These difficulties may have contributed to later problems with career attainment and confidence in relationships. Seventy-seven percent of parents stated that their child was experiencing difficulties at school relating to NF1 (n = 51). Of the subjects at risk of having a child with NF1 and who knew about NF1 before having their family (n = 32), 45% said that it had influenced their reproductive decisions. Of 29 subjects who were still considering children, 41% wished to have prenatal diagnosis in a future pregnancy, but only three subjects stated that they would terminate an affected pregnancy.

Adolescent↗
PubMed1993

A new ectrodactyly syndrome?

We report a fetus with hydrops, ectrodactyly, syndactyly, duplication of the great toes and several other features. From a review of the literature we suggest that this constellation of abnormalities has not previously been reported.

Abnormalities, Multiple↗
PubMed1993

Tandem duplication within a neurofibromatosis type 1 (NF1) gene exon in a family with features of Watson syndrome and Noonan syndrome.

Type 1 neurofibromatosis (NF1), Watson syndrome (WS), and Noonan syndrome (NS) show some overlap in clinical manifestations. In addition, WS has been shown to be linked to markers flanking the NF1 locus and a deletion at the NF1 locus demonstrated in a WS patient. This suggests either that WS and NF1 are allelic or that phenotypes arise from mutations in very closely linked genes. Here we provide evidence for the former by demonstrating a mutation in the NF1 gene in a family with features of both WS and NS. The mutation is an almost perfect in-frame tandem duplication of 42 bases in exon 28 of the NF1 gene. Unlike the mutations previously described in classical NF1, which show a preponderance of null alleles, the mutation in this family would be expected to result in a mutant neurofibromin product.

Amino Acid Sequence↗
PubMed1992

Monozygotic twinning and Wiedemann-Beckwith syndrome.

Monozygotic (MZ) twinning occurs with relatively high frequency in Wiedemann-Beckwith syndrome (WBS). Ten sets of MZ twins with WBS have been reported. Nine of these have been female and in each case the twins were discordant for the WBS phenotype. The tenth set was male. They were concordant for WBS and both had a duplication of chromosome 15 which they shared in common with their phenotypically normal mother. The WBS gene has been assigned to the locus 11p15 and there appear to be several different genetic mechanisms involving this locus which all give rise to WBS. An imprinting effect for the WBS gene has been proposed because of the transmission of the gene preferentially through the maternal line in some large pedigrees. We describe two further sets of female MZ twins with WBS. One pair is concordant and one discordant for the condition. The possible genetic mechanisms involved in the expression of WBS are discussed, with particular reference to twinning, genomic imprinting and X-inactivation which is thought to be associated with the occurrence of MZ twinning in females.

Beckwith-Wiedemann Syndrome↗
PubMed1992

Recurrent Wiedemann-Beckwith syndrome with inversion of chromosome (11)(p11.2p15.5).

A baby with Wiedemann-Beckwith syndrome (WBS) and her phenotypically normal mother carried the same paracentric inversion, inv(11)(p11.2 15.5), in the short arm of chromosome 11. A fetus, sib of the affected baby, had the same inversion and ultrasound scan showed exomphalos. The maternal grandmother is clinically and cytogenetically normal. The pattern of affection in this family is consistent with the suggestion that WBS can be caused by lack of a maternally imprinted gene at 11p15.5, and that in this family the inversion disrupts that gene.

Beckwith-Wiedemann Syndrome↗