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M Baraitser

Publications and source records attributed to M Baraitser.

At least 73 records · Page 4Linked to original sources
PubMed1992

Pelizaeus-Merzbacher disease: detection of mutations Thr181----Pro and Leu223----Pro in the proteolipid protein gene, and prenatal diagnosis.

A family with an apparent history of X-linked Pelizaeus-Merzbacher disease presented for genetic counseling, requesting carrier detection and prenatal diagnosis. RFLP analysis using the proteolipid protein (PLP) gene probe was uninformative in this family. A prenatal diagnosis on a chorionic villus sample (CVS) was carried out using single-strand conformation polymorphism (SSCP) analysis of a variant in exon 4 of the PLP gene. The fetus was predicted to be unaffected. Sequencing of the exon from the CVS, the predicted-carrier mother, and the obligate-carrier grandmother revealed an A-to-C change at nucleotide 541 in the two women but not in the fetus. As this change results in a Thr-to-Pro change at amino acid 181 in a region of the gene predicted to be part of a transmembrane segment, it was concluded that this was the mutation causing the disease in this family. In addition, in a second family, an exon 5 variant band pattern on SSCP analysis was shown by sequencing to be due to a T-to-C change at nucleotide 668. This results in a Leu-to-Pro change in a carrier mother and in her two affected sons. These results provide further examples of mutations in PLP that cause Pelizaeus-Merzbacher disease and illustrate the value of SSCP in genetic analysis.

Amino Acid Sequence↗
PubMed1991

Genetic and clinical heterogeneity of Stickler syndrome.

We have studied 6 multigeneration Stickler syndrome families. Manifestations of the syndrome in the families included myopia, deafness, arthritis, characteristic facial changes with "flat" midface and cleft palate, although not all these were present in all families. COL2A1 has been implicated as a gene which can give rise to Stickler syndrome based on evidence from 2 large families which each showed significant linkage between the disease locus and restriction fragment length polymorphisms for the gene (Francomano CA, Lieberfarb RM, Hirose T, Maumenee IH, Streeten EA, Meyers DA, Pyeritz RE (1987): Genomics 1:293-296; Knowlton RG, Weaver EJ, Struyk AF, Knobloch WH, King RA, Norris K, Shamban A, Uitoo J, Jimenez SA, Prockop DJ (1989): Am J Hum Genet 45:681-688). We have found crossovers between the disease locus and COL2A1 in 2 families with Stickler syndrome. This could be explained by either genetic heterogeneity or the actual mutation being in a closely linked, currently unrecognized gene. We found a weakly positive overall lod score (z = 0.96 at theta = 0.10) suggesting that genetic heterogeneity is a more likely explanation. In one family, with typical findings, a translocation t5;17 (q15:q23) was found to segregate with the disease in 4 affected relatives. In view of the possible heterogeneity, although no crossovers with COL2A1 were seen in this family, either of these breakpoints could be the position of a further disease causing gene.

Abnormalities, Multiple↗
PubMed1991

Pelizaeus-Merzbacher disease: classical or connatal?

The clinical features and investigation results of 7 patients with Pelizaeus-Merzbacher disease (PMD) are described; one patient had a brain biopsy and two patients had an autopsy. This paper tries to differentiate the clinical features of the connatal and classical types of PMD. Transient stridor and nystagmus were early signs in both types of PMD. Our findings support the view that the more severe connatal form shows rapid neurological deterioration from an early age leading to death usually in the first decade. In younger patients in whom the evolution is still unclear, severe feeding problems and extrapyramidal features may suggest the connatal form. By contrast, in the classical form of PMD, cerebellar signs and cognitive deterioration are more prominent with a more slowly progressive course. Nuclear magnetic resonance imaging and brainstem auditory evoked potentials were very helpful in supporting the diagnosis of PMD either in a known affected family or in sporadic cases, but were not useful in distinguishing between the two types of PMD. Genetic counseling in this condition is difficult, particularly in the connatal form in which inheritance may be either X-linked or autosomal recessive.

Age Factors↗
PubMed1991

Atypical facio-scapulo-humeral muscular dystrophy--a counselling dilemma.

In an isolated male patient, differentiation between Facio-Scapulo-Humeral Muscular Dystrophy (FSH) and Becker Muscular Dystrophy (BMD) may be difficult. To emphasise this point, we report a patient, whose features are atypical of FSH. Details of his daughter who now manifests similar presenting features, are provided. The pitfalls posed for the genetic counsellor by FSH presenting in an atypical manner which clinically overlaps with genetically distinct conditions are discussed in the light of this pedigree.

Adult↗
PubMed1991

Severe microcephaly associated with congenital varicella infection.

A case of second-trimester congenital varicella infection, in association with isolated microcephaly and severe brain damage, is reported, and cases of classical congenital varicella syndrome are compared on a clinical and immunological basis. This case, together with others cited in the literature, suggests that congenital varicella infection may lead to microcephaly and neurological abnormalities, without the presence of skin lesions. Although first-trimester infection has been considered the most likely to produce congenital abnormalities, the second trimester may be more commonly implicated; indeed there may not be a critical period if varicella causes secondary disruption of differentiated tissues.

Atrophy↗
PubMed1991

Heterogeneity in dominant anterior segment malformations.

Peters' anomaly is usually a sporadic or autosomal recessive condition. We present three families whose members had dominantly inherited anterior segment anomalies with variable expression, including typical Peters' anomaly in at least one family member. Slit-lamp examination of parents and family members of children with Peters' anomaly is therefore important to exclude dominant inheritance.

Abnormalities, Multiple↗
PubMed1991

Oculofacialbulbar palsy in mother and son: review of 26 reports of familial transmission within the 'Möbius spectrum of defects'.

We report a mother and son with 5th, 6th, 7th, and bulbar cranial nerve paralysis, who had two similarly affected relatives. None of them had primary skeletal defects. Twenty-six previous reports of familial cases within the heterogeneous 'Möbius spectrum of defects' were reviewed. When cranial nerve palsies were associated with a primary skeletal defect, familial transmission was not found. No recurrence was noted in 31 cases with cranial nerve palsies associated with oral abnormalities and limb defects. The term Möbius syndrome should be restricted to cases with congenital 6th and 7th nerve paralysis with skeletal defects, who have a low recurrence risk (2%). The features in an index case which may indicate a higher risk of recurrence are the absence of skeletal defects, isolated facial palsy, deafness, ophthalmoplegia, and digital contractures. A recurrence risk of 25 to 30% in these cases appears reasonable.

Adult↗
PubMed1991

Balanced t(6;8)(6p8p;6q8q) and the CHARGE association.

A girl is described with bilateral retinal colobomata, Fallot's tetralogy, unilateral choanal atresia, abnormalities of the external ears, bilateral sensorineural deafness, a unilateral facial nerve palsy, and a tracheo-oesophageal fistula. A clinical diagnosis of the CHARGE association was made. She had an apparently balanced whole arm translocation involving chromosomes 6 and 8. Parental karyotypes were normal.

Abnormalities, Multiple↗
PubMed1991

Pitfalls in counselling: the craniosynostoses.

We describe three families to highlight the variability of expression and penetrance that can occur in the craniosynostoses. In two of the families, gene carriers were only identified in retrospect by looking at photographs of other family members. In the third family, identical twins were initially thought to be discordant for sagittal craniosynostosis until early skull x rays were examined and both were found to be affected. The dilemmas faced when counselling these families are discussed.

Adult↗
PubMed1991

Sibs with mental retardation, supraorbital sclerosis, and metaphyseal dysplasia: frontometaphyseal dysplasia, craniometaphyseal dysplasia, or a new syndrome?

A brother and sister are presented with unusual facies, bilateral mixed hearing loss, mental retardation, and widespread radiological abnormalities. The clinical and radiological evidence for and against the two most likely diagnoses of frontometaphyseal dysplasia and craniometaphyseal dysplasia is considered.

Abnormalities, Multiple↗