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Biomedical subjects

A Slavotinek

Publications and source records attributed to A Slavotinek.

At least 19 recordsLinked to original sources

Mutation analysis of the FRAS1 gene demonstrates new mutations in a propositus with Fraser syndrome.

Fraser syndrome (OMIM 219000) is a rare, autosomal recessive condition with classical features of cryptophthalmos, syndactyly, ambiguous genitalia, laryngeal, and genitourinary malformations, oral clefting and mental retardation. Mutations causing loss of function of the FRAS1 gene have been demonstrated in five patients with Fraser syndrome. However, no phenotype-genotype correlation was established and there was evidence for genetic heterogeneity. Fraser syndrome is rare and the FRAS1 gene has 75 exons, complicating mutation screening in affected patients. We have screened two patients who fulfilled the diagnostic criteria for Fraser syndrome and three patients with related phenotypes (two patients with Manitoba oculotrichoanal syndrome and one patient with unilateral cryptophthalmos and labial fusion) for mutations in FRAS1 to increase the molecular genetic data in patients with Fraser syndrome and related conditions. We report two new mutations in a patient with Fraser syndrome, a frameshift mutation and a deletion of two amino acids that we consider pathogenic as both alter the NG2-like domain of the protein. Although we are still unable to clarify a phenotype-genotype relationship in Fraser syndrome, our data add to the list of mutations associated with this syndrome.

Adolescent↗

Fryns syndrome phenotype caused by chromosome microdeletions at 15q26.2 and 8p23.1.

BACKGROUND: Fryns syndrome (FS) is the commonest autosomal recessive syndrome in which congenital diaphragmatic hernia (CDH) is a cardinal feature. It has been estimated that 10% of patients with CDH have FS. The autosomal recessive inheritance in FS contrasts with the sporadic inheritance for the majority of patients with CDH and renders the correct diagnosis critical for accurate genetic counselling. The cause of FS is unknown. METHODS: We have used array comparative genomic hybridisation (array CGH) to screen patients who have CDH and additional phenotypic anomalies consistent with FS for cryptic chromosome aberrations. RESULTS: We present three probands who were previously diagnosed with FS who had submicroscopic chromosome deletions detected by array CGH after normal karyotyping with G-banded chromosome analysis. Two female infants were found to have microdeletions involving chromosome band 15q26.2 and one male had a deletion of chromosome band 8p23.1. CONCLUSIONS: We conclude that phenotypes similar to FS can be caused by submicroscopic chromosome deletions and that high resolution karyotyping, including array CGH if possible, should be performed prior to the diagnosis of FS to provide an accurate recurrence risk in patients with CDH and physical anomalies consistent with FS.

Abnormalities, Multiple↗

Two unique patients with trisomy 18 mosaicism and molecular marker studies.

We report two unusual patients with trisomy 18 mosaicism presenting with minor anomalies and failure to thrive in the first year of life. Chromosome analysis showed trisomy 18 in 30/30 peripheral blood lymphocytes in both children. Analysis of skin fibroblasts in the first child showed normal female chromosomes in 30/30 cells, and the fibroblast karyotype in the second child showed mosaicism for tetrasomy 18p, trisomy 18, and normal female chromosomes (karyotype 47,XX, +i(18)(p10)[47]/47,XX, +18[9] /46,XX[4]). Trisomy 18 commonly results from nondisjunction at maternal meiosis II (MII). Nondisjunction at maternal MII has also been postulated to be the initial step in the formation of tetrasomy 18p. In our second case, the additional chromosome 18 was the result of maternal nondisjunction at MII, consistent with this hypothesis. In the first case, nondisjunction at maternal meiosis I (MI) was responsible for the extra chromosome 18.

Aneuploidy↗

Mutation of a gene encoding a putative chaperonin causes McKusick-Kaufman syndrome.

McKusick-Kaufman syndrome (MKKS, MIM 236700) is a human developmental anomaly syndrome comprising hydrometrocolpos (HMC), postaxial polydactyly (PAP) and congenital heart disease (CHD). MKKS has been mapped in the Old Order Amish population to 20p12, between D20S162 and D20S894 (ref. 3). Here we describe the identification of a gene mutated in MKKS. We analysed the approximately 450-kb candidate region by sample sequencing, which revealed the presence of several known genes and EST clusters. We evaluated candidate transcripts by northern-blot analysis of adult and fetal tissues. We selected one transcript with widespread expression, MKKS, for analysis in a patient from the Amish pedigree and a sporadic, non-Amish case. The Old Order Amish patient was found to be homozygous for an allele that had two missense substitutions and the non-Amish patient was a compound heterozygote for a frameshift mutation predicting premature protein truncation and a distinct missense mutation. The MKKS predicted protein shows amino acid similarity to the chaperonin family of proteins, suggesting a role for protein processing in limb, cardiac and reproductive system development. We believe that this is the first description of a human disorder caused by mutations affecting a putative chaperonin molecule.

Abnormalities, Multiple↗

Two cases with interstitial deletions of chromosome 2 and sex reversal in one.

We present two children with de novo interstitial deletions of the long arm of chromosome 2 (karyotypes 46,XY, del(2)(q31.1q31.3) and 46,XY, del(2)(q24.3q31.3), respectively). The first child had severe learning difficulties, growth retardation, unilateral ptosis, small palpebral fissures, a cleft uvula, and bilateral cutaneous syndactyly of the second and third toes. Despite her male karyotype, she had female external genitalia with hypoplasia of the clitoris and labia minora. This is the first reported case of feminization of the external genitalia in a genotypic male with an interstitial deletion of chromosome 2q31 and adds to the growing amount of evidence for a gene involved in sex determination in this chromosome region. The second child had severe mental and growth retardation, ptosis, down-slanting palpebral fissures, low-set ears, micrognathia, finger camptodactyly, and brachysyndactyly of the second to fifth toes. The clinical manifestations associated with deletions of 2q31 to 2q33 are similar to those found with proximal deletions at 2q24 to 2q31 and of band 2q24, suggesting that the phenotype may result from haploinsufficiency for one or more genes located at 2q31. Microsatellite marker studies showed that both children had paternally derived deletions that included the HOXD gene cluster and the EVX2, DLX1, and DLX2 genes known to be important in limb development.

Abnormalities, Multiple↗

Screening for submicroscopic chromosome rearrangements in children with idiopathic mental retardation using microsatellite markers for the chromosome telomeres.

Recently much attention has been given to the detection of submicroscopic chromosome rearrangements in patients with idiopathic mental retardation. We have screened 27 subjects with mental retardation and dysmorphic features for such rearrangements using a genetic marker panel screening. The screening was a pilot project using markers from the subtelomeric regions of all 41 chromosome arms. The markers were informative for monosomy in both parents at 3661902 loci (40.6%, 95% confidence interval 37.0-44.2%) in the 22 families where DNA was available from both parents. In two of the 27 subjects, submicroscopic chromosomal aberrations were detected. The first patient had a 5-6 Mb deletion of chromosome 18q and the second patient had a 4 Mb deletion of chromosome 1p. The identification of two deletions in 27 cases gave an aberration frequency of 7.5% without adjustment for marker informativeness (95% confidence interval 1-24%) and an estimated frequency of 18% if marker informativeness for monosomy was taken into account. This frequency is higher than previous estimates of the number of subtelomeric chromosome abnormalities in children with idiopathic mental retardation (5-10%) although the confidence interval is overlapping. Our study suggests that in spite of the low informativeness of this pilot screening, submicroscopic chromosome aberrations may be a common cause of dysmorphic features and mental retardation.

Adolescent↗

Brachydactyly type B: case report and further evidence for clinical heterogeneity.

We present a male child with digital and radiographic findings consistent with brachydactyly type B. His left hand had 2-4 syndactyly, shortened first and fifth digits and single palmar and fifth finger flexion creases. The nail on the second finger was hypoplastic. The right hand had a small thumb and curving of the second finger towards the midline. The left foot had a short left hallux with an absent nail, 2-4 syndactyly and an absent toe. His right foot had a short, dorsiflexed hallux with a hypoplastic nail, 2-3 syndactyly and an overlapping toe. Radiographs showed asymmetrical hypoplasia of the middle and terminal phalanges and there were no extra-articular findings to suggest Sorsby syndrome. Brachydactyly type B has classically been described as hypoplasia or absence of the terminal phalanges with absent nails. Although other digital anomalies have previously been described with brachydactyly type B, the absent digit, atypical syndactyly and marked asymmetry in this child make this case a good illustration of the clinical heterogeneity that can be associated with this type of brachdactyly. We provide a brief review of syndromes in which similar digital malformations have been reported.

Hand Deformities, Congenital↗

Unilateral tibial aplasia, pre-axial polysyndactyly, vertebral anomalies and imperforate anus.

Tibial hemimelia is a rare malformation that can be isolated or found with other skeletal abnormalities. We describe a fetus with unilateral tibial aplasia, ipsilateral pre-axial polysyndactyly and femoral hypoplasia, ventriculomegaly, anal atresia and rib and vertebral anomalies. We believe that this combination of malformations has not previously been described.

Abnormalities, Multiple↗

Monosomy 1p36.

We have reviewed published reports on patients with segmental aneusomy for chromosome 1p36 to help geneticists and other health professionals in the recognition of this emerging chromosomal syndrome. Terminal deletions of the short arm of chromosome 1 are associated with hypotonia and developmental delay (usually severe), growth abnormalities (growth retardation, microcephaly, obesity), and craniofacial dysmorphism with a large anterior fontanelle, prominent forehead, deep set eyes, flat nasal bridge and midface hypoplasia, ear asymmetry, a pointed chin, and orofacial clefting. Minor cardiac malformations, cardiomyopathy, seizures, and ventricular dilatation are the more common additional findings. Sensorineural hearing loss and variable ophthalmological anomalies have also been frequently observed. Although the deletions can be detected by high resolution cytogenetic studies, confirmation by fluorescence in situ hybridisation is required in most cases. The majority of deletions are maternally derived. Molecular characterisation of 1p36 deletions has been undertaken in several cases, and it is likely that this condition is a contiguous gene deletion syndrome.

Adolescent↗

A girl with ectodermal dysplasia, choanal atresia and polysyndactyly.

We present a 3-year-old child with clinical features of ectodermal dysplasia comprising sparse hair, dystrophic and ridged nails and bilateral obstruction of the nasolacrimal ducts. Additional findings were unilateral choanal atresia, bilateral syndactyly of the feet and polydactyly. We discuss the differential diagnosis of these clinical findings.

Abnormalities, Multiple↗

A boy with severe manifestations of type A1 brachydactyly.

We describe a male with type A1 brachydactyly, a descendant of Drinkwaters second family. In addition to absence of the middle phalanges of his hands and feet he has generalised skeletal abnormalities, nystagmus and a squint. We suggest that his clinical findings represent the more severe manifestations of this autosomal dominant gene.

Adolescent↗

Familial patent ductus arteriosus: a further case of CHAR syndrome.

We report on a family with patent ductus arteriosus, a distinctive facial appearance with eyebrow flare, a short nose and "duck-bill lips," polydactyly, and fifth finger clinodactyly. The facial traits were consistent with CHAR syndrome. We provide further evidence for evolution of the phenotype with age and describe the previously unreported finding of interstitial polydactyly in this syndrome.

Abnormalities, Multiple↗

Differences between treatment seekers in an obese population: medical intervention vs. dietary restriction.

This study examined two groups of people who were pursuing treatment for obesity: either medical intervention (a hospital group; N = 20) or support for dietary restriction (a community group; N = 18). This study addressed four questions: (1) Were there differences between the two groups in terms of their psychological distress (as measured by the Symptom Checklist)? (2) Does binge eating moderate psychological distress? (3) Do feelings of ineffectiveness moderate psychological distress? and (4) Which variables best accounted for group membership (i.e., type of treatment sought)? Results suggested that the hospital group was significantly more distressed than the community group. However, there were no differences between the two groups with respect to binge eating or feelings of ineffectiveness. These findings suggest that it is the effects of morbid obesity that are most likely to moderate psychological distress.

Adult↗

Paternally inherited duplications of 11p15.5 and Beckwith-Wiedemann syndrome.

We present a three generation family in which a father and son have a balanced chromosome translocation between the short arms of chromosomes 5 and 11 (karyotype 46,XY,t(5;11)(p15.3;p15.3)). Two family members have inherited the unbalanced products of this translocation and are trisomic for chromosome 11p15.3-->pter and monosomic for chromosome 5p15.3-->pter (karyotype 46,XY,der(5)t(5;11)(p15.3;p15.3)pat). Paternally derived duplications of 11p15.5 are associated with Beckwith-Wiedemann syndrome (BWS) and both family members trisomic for 11p15.5 had prenatal overgrowth (birth weights >97th centile), macroglossia, coarse facial features, and broad hands. We review the clinical features of BWS patients who have a paternally derived duplication of 11p15.5 and provide evidence for a distinct pattern of dysmorphic features in those with this chromosome duplication. Interestingly, our family is the fifth unrelated family to be reported with a balanced reciprocal translocation between the short arms of chromosomes 5 and 11. The apparently non-random nature of this particular chromosome translocation is suggestive of sequence homology between the two chromosome regions involved in the translocation.

Adolescent↗

The phenotypic effects of chromosome rearrangement involving bands 7q21.3 and 22q13.3.

We report a family in which the proband has a direct insertion of band 7q21.3 into chromosome 22 at 22q13.3, karyotype 46,XX,dir ins(22;7)(q13.3;q21.2q22.1). Two of her children have unbalanced chromosome rearrangements involving 7q21.3, with one girl monosomic for the region and a boy trisomic for the region. The child monosomic for band 7q21.3 has a split hand/split foot (SHSF) anomaly and her clinical features are consistent with the 7q21-q22 contiguous gene deletion syndrome. In situ hybridisation studies have shown that the proband and her son have a submicroscopic deletion of chromosome band 22q13.3. Interstitial deletions of this chromosome band have rarely been reported.

Adult↗