Non-dermatological complications and genetic aspects of the Rothmund-Thomson syndrome

We report two new cases of Rothmund-Thomson syndrome which emphasize the less well-known non-dermatological complications, namely: hypodontia, soft tissue contractures, proportionate short stature, hypogonadism, anaemia and osteogenic sarcoma. Genetic analysis of these and previously reported pedigrees supports autosomal recessive inheritance.     

Course of autosomal recessive polycystic kidney disease (ARPKD) in siblings: a clinical comparison of 20 sibships

Forty-two children out of 20 sibships with autosomal recessive polycystic kidney disease were observed pro- and retrospectively over a mean period of 3.7 years in a long-term study on cystic kidney diseases in children. The intra- and interfamilial variability in terms of age at diagnosis, administration of antihypertensive therapy, liver affection, and renal function were evaluated. According to the 1971 subclassification of Blyth & Ockenden, defining different grades of severity, 12 patients were assigned to the perinatal, nine to the neonatal, 13 to the infantile, and eight to the juvenile subtype of autosomal recessive polycystic kidney disease. In 11 of the 20 families different subtypes were observed among affected siblings. In seven families, affected sibs belonged to adjacent subtypes, while major intrafamilial differences were observed in only four families. The defined subtypes, therefore, cannot be regarded as appropriate in distinguishing genetic groups of autosomal recessive polycystic kidney disease. With respect to the severity of autosomal recessive polycystic kidney disease, there is a wide spectrum of phenotypic manifestations, ranging from stillbirths to mildly affected adults, while intrafamilial variability of the clinical picture is generally small with multiple allelism as the most likely genetic explanation. Age at death, however, showed gross variation in eight sibships. Differences in the clinical course between several siblings cannot be explained by a sex influence in autosomal recessive polycystic kidney disease.     

FAMILIAL FANCONI SYNDROME WITH MALABSORPTION AND GALACTOSE INTOLERANCE, NORMAL KINASE AND TRANSFERASE ACTIVITY

ABSTRACT. Aperia, A., Bcrgqvist, G., Linné, T. and Zetterström, R. (Department of Paediatrics, Karolinska Institute, St. Göran's Children's Hospital, Stockholm, Sweden). Familial Fanconi syndrome with malabsorption and galactose intolerance, normal kinase and transferase activity. A report on two siblings. Acta Paediatr Scand, 70:527,.–Two siblings of Turkish-Assyrian extraction, whose parents were first cousins, had poor appetite, slow weight gain and retarded psychomotor development. When given milk the galactose concentration in blood increased. An oral galactose load showed a markedly reduced capacity to metabolize galactose. Fanconi syndrome was present as in classical galactosemia. A galactose-free diet reduced the aminoaciduria but did not normalize the renal tubular function nor the children's general condition. Galactokinase and galactose-1-phosphate uri-dyltransferase activities in red blood cells were normal. The physical appearance of the children (sparse subcutaneous fat, thin extremities and distended abdomen) and the results of vitamin A and xylose absorption tests, were in accordance with a malabsorption condition. Glucose, however, seemed to be absorbed normally from the gut. There was no evidence of significant primary liver disease. Since the condition did not normalize with a galactose-free diet, an enzyme defect of galactose metabolism is unlikely. Instead, a more general transport defect with autosomal recessive inheritance is proposed.     

Mental retardation,unusual face,and intrauterine growth retardation: A new recessive syndrome?

We describe two mentally retarded sisters with intrauterine growth retardation and subsequent dwarfism and an unusal and characteristic face together with two other unrelated patients with similar manifestations. These four patients may represent a new autosomal recessive syndrome.     

Optimal discrimination of an Abyssinian cat recessive retinal degeneration: a short electroretinogram protocol is more efficient than a long one

AIM: To determine the diagnostic efficiency of scores in a long protocol ectroretinogram (ERG) for Abyssinian cat slow recessive rod/cone dystrophy. METHODS: Kittens (n = 22) were bred from homozygous,affected and heterozygous normals. Ophthalmoscopy was regularly performed and disease signs noted. Cats (age > or = 8 months, 40 sessions, 1-3 repeats) were dark-adapted overnight, anaesthetized and simultaneous binocular ERG recorded using a long protocol. Conventional a- and b-amplitudes and peak implicit times were measured and b/a ratios calculated, initially only for ERG to the maximum photopic and scotopic stimulus. Principal components factor analysis was applied to various subsets of these scores plus age at testing. RESULTS: Six cats with ophthalmoscopic change were classed as affected. Three cats, one tested three times, were suspect. The rest were considered normal. The first analysis, of 80 eyes and 37 parameters, showed that the first factor was the only effective one. Using it, the groups overlapped 5%, scotopic amplitudes and b/a ratios loaded higher than peak times, the eyes were very similar, and age and photopic b/a ratios loaded poorly. The groups were discriminable with all the data. A second analysis, with eyes averaged and the 20 measures loading over 0.5 on the first factor, showed better group separation on factor I alone. An iterative search with varying data sets found that factor I was optimal, with eight ERG measures to the three brightest scotopic and one brightest photopic response. It produced a large absolute separation and classified the suspects consistently. With b/a ratios on these four ERG also included, 12 parameters gave better separation. CONCLUSION: Twelve scores on four ERG separate affected from normal cats with a wide gap and consistently classify suspects. It may work for earlier ages. Additional data probably adds noise. This combination of optimal scores needs confirmation in new data.     

PET neuroimaging and mutations in the DJ-1 gene

Summary. Mutations in the DJ-1 gene lead to autosomal recessive early-onset parkinsonism. We performed F-DOPA and FDG PET neuroimaging in two parkinsonism patients homozygous for DJ-1 mutations, three relatives heterozygous for a DJ-1 mutation and one non-carrier, all from the originally described kindred from The Netherlands. Their characteristics were compared to those of typical Parkinsons disease patients and healthy controls. Both parkinsonism patients had reduced F-DOPA uptake concordant with typical Parkinsons disease. In the, clinically unaffected, heterozygous relatives, F-DOPA metabolism was unremarkable, thus not suggesting a dosage effect of the DJ-1 gene.     

Mutation in the cartilage-derived morphogenetic protein-1 (CDMP1) gene in a kindred affected with fibular hypoplasia and complex brachydactyly (DuPan syndrome)

The present authors have previously described a consanguineous Pakistani family with fibular hypoplasia and complex brachydactyly (DuPan syndrome) inherited as an autosomal recessive trait. All affected individuals showed either reductions or absence of bones in the limbs, and appendicular bone dysmorphogenesis with unaffected axial bones. Obligate heterozygote parents were phenotypically normal. Mutations in the cartilage-derived morphogenetic protein 1 (CDMP1) gene have been reported in two acromesomelic chondrodysplasias (i.e. Hunter-Thompson type and Grebe type) which are phenotypically related to DuPan syndrome. CDMP1, a member of the transforming growth factor beta super-family of secreted signalling molecules, has been reported to regulate limb patterning and distal bone growth. Therefore, the present authors examined genomic DNA from the family with DuPan syndrome for mutations in the CDMP1 gene. Affected individuals were homozygous for a missense mutation, T1322C, in the coding region of the CDMP1 gene. This mutation was not found in 44 control subjects of Pakistani origin. The T1322C change predicts a leu441pro substitution in the mature domain of the CDMP1 protein. This is likely to cause a conformational change in the CDMP1 protein that influences the expression of genes which are required for normal bone development. This finding extends the spectrum of phenotypes produced by defects in the CDMP1 gene.     

Skin fragility and hypohidrotic ectodermal dysplasia resulting from ablation of plakophilin 1

We report a 2-year-old boy with an unusual autosomal recessively inherited skin disease comprising trauma-induced skin fragility and congenital ectodermal dysplasia affecting hair, nails and sweat glands. Skin biopsy showed widening of intercellular spaces between keratinocytes and ultrastructural findings of small, poorly formed desmosomes with reduced connections to the keratin filament cytoskeleton. Immunohistochemical analysis revealed a complete absence of staining for the accessory desmosomal plaque protein plakophilin 1 (PKP1; band 6 protein). The affected individual was a compound heterozygote for null mutations on both alleles of the PKP1 gene. Both mutations occurred within the amino terminus of PKP1, the domain which normally binds the cytoskeletal keratin filament network to the cell membrane. Apart from its localization within desmosomal plaques, PKP1 may also be present within the cytoplasm and nucleus and has putative roles in signal transduction and regulation of gene activity. The clinicopathological observations in this patient demonstrate the relevance of PKP1 to desmosome formation, cutaneous cell-cell adhesion and epidermal development and demonstrate the specific manifestations of human functional knockout mutations in this gene.     

17 alpha-hydroxylase deficiency in a genetic male and female sibling pair

The diagnosis of congenital adrenal hyperplasia due to a deficiency of the enzyme 17 alpha-hydroxylase was made in a genetic male and female sibling pair born of parents who were first cousins. The genetic male was a phenotypic female who presented with primary amenorrhea and mild hypertension. The genetic female exhibited absence of secondary sexual characteristics and severe hypertension. The plasma steroid data confirmed the diagnosis of 17 alpha-hydroxylase deficiency in both subjects: low 17 alpha-hydroxyprogesterone, elevated desoxycorticosterone, elevated corticosterone and elevated progesterone. These are the first case reports of 17 alpha-hydroxylase deficiency in a male-female sibling pair, and they add support to the hypothesis that this is an autosomal recessive disorder.