Dyschromatosis universalis hereditaria: familial case and ultrastructural skin investigation

We present three families with infantile myofibromatosis (IM; OMIM no. 228550) inherited in an autosomal dominant (AD) manner. These three pedigrees prompted re-assessment of pedigrees available within the genetic, oncologic, surgical, and pathologic literature, which suggest autosomal recessive (AR) inheritance. All familial IM may be interpreted as AD or, alternatively, there may be genetic heterogeneity for IM. As most nodules tend to regress spontaneously, familial history may be difficult to obtain and/or confirm. Clinical diagnosis and establishment of inheritance pattern can be important for prognosis and the recognition that other family members may be affected.     

Probable dominant inheritance in Blount's disease

A family is described with infantile Blount's disease ( tibia vara ) following an autosomal dominant mode of inheritance. The bow legs in infancy of family members seem to improve with age, although the literature appears to imply that this is a progressive condition. It is speculated that infantile Blount's disease may be inherited as an autosomal dominant condition with variable penetrance, and that genetic factors have been noted only infrequently, as parents may have improved with age or have been affected only mildly.     

Does autosomal dominant pseudoxanthoma elasticum exist?

Pseudoxanthoma elasticum (PXE) is a progressive disorder of elastic fibers in skin, eyes, and arterial walls. It is caused by mutations in the ABCC6 gene. Most patients are sporadic cases. The majority of familial cases show autosomal recessive (AR) inheritance, but autosomal dominant (AD) inheritance has also been reported. We reviewed the literature on AD PXE and we studied in detail, both clinically and by DNA studies, a selection of potentially AD pedigrees from our patient population consisting of 59 probands and their family members. Individuals were considered to have definite PXE if they had two of the following three criteria: characteristic ophthalmologic signs, characteristic dermatologic signs, and a positive skin biopsy. In the literature we found only three families with definite PXE in two successive generations and no families with definite PXE in three or more generations. Our own data set comprised three putative AD families. Extensive DNA studies revealed a mutation in only one ABCC6 allele in the patients of these families. Only one of our families showed definite PXE in two generations. Linkage studies revealed that pseudodominance was unlikely in this family. In the other two families AD PXE could not be confirmed after extensive clinical examinations and application of our criteria, since definite PXE was not present in two or more generations. Conclusion: the inheritance pattern in PXE usually is AR. Part of the phenotype in family members of PXE patients might be due to expression in heterozygous carriers of an AR disease. AD inheritance in PXE may exist, but is both after careful literature study and in our patient material much rarer than previously thought.     

Denaturing gradient gel electrophoresis analysis of the tissue nonspecific alkaline phosphatase isoenzyme gene in hypophosphatasia

Hypophosphatasia, a heritable form of rickets/osteomalacia, was first described in 1948. The biochemical hallmark, subnormal alkaline phosphatase (ALP) activity in serum, reflects a generalized disturbance involving the tissue-nonspecific isoenzyme of ALP (TNSALP). Deactivating mutations in the gene that encodes TNSALP have been reported in patients worldwide. Nevertheless, hypophosphatasia manifests an extraordinary range of clinical severity spanning death in utero to merely premature loss of adult teeth. There is no known medical treatment. To delineate the molecular pathology which explains the disease variability and to clarify the pattern(s) of inheritance for mild cases of hypophosphatasia, we developed comprehensive mutational analysis of TNSALP. High efficiency of mutation detection was possible by denaturing gradient gel electrophoresis (DGGE). Primers and conditions were established for all TNSALP coding exons (2-12) and adjacent splice sites so that the amplicons incorporated a GC clamp on one end. For each amplicon, the optimum percentage denaturant was determined by perpendicular DGGE. In 19 severely affected pediatric subjects (having perinatal or infantile hypophosphatasia or early presentation during childhood) from among our large patient population, we detected 2 TNSALP mutations each in 16 patients (84%) as expected for autosomal recessive disease. For 2 patients (11%), only 1 TNSALP mutation was detected by DGGE. However, one subject (who died from perinatal hypophosphatasia) had a large deletion as the second mutation. In the other (with infantile hypophosphatasia), no additional mutation was detected by DNA sequencing of all protein-coding exons. Possibly, she too has a deletion. For the final patient, with unclassifiable hypophosphatasia (5%), we detected only a single mutation which has been reported to cause relatively mild autosomal dominant disease; the other allele appeared to be intact. Hence, DGGE analysis was 100% efficient in detecting mutations in the coding exons and adjacent splice sites of TNSALP in this group of severely affected patients but, as expected, failed to detect a large deletion. To date, at least 78 different TNSALP mutations (in about 70 hypophosphatasia patients) have been reported globally. In our large subset of severely affected patients, we identified 8 novel TNSALP mutations (Ala34Ser, Val111Met, Delta G392, Thr117His, Arg206Gln, Gly322Arg, Leu397Met, and Gly409Asp) and 1 new TNSALP polymorphism (Arg135His) furthering the considerable genotypic variability of hypophosphatasia.     

Pseudodominant inheritance of spondylocostal dysostosis type 1 caused by two familial delta-like 3 mutations

Spondylocostal dysostoses (SCD) are a heterogeneous group of disorders of axial skeletal malformation characterized by multiple vertebral segmentation defects and rib anomalies. Sporadic cases with diverse phenotypes, sometimes including multiple organ abnormalities, are relatively common, and monogenic forms demonstrating autosomal recessive (AR) and, more rarely, autosomal dominant (AD) inheritance have been reported. We previously showed that mutations in delta-like 3 (DLL3), a somitogenesis gene that encodes a ligand for the notch signaling pathway, cause AR SCD with a consistent pattern of abnormal segmentation. We studied an SCD family previously reported to show AD inheritance, in which the phenotype is similar to that in AR cases. Direct DLL3 sequencing of individuals in two generations identified the affected father as homozygous for a novel frameshift mutation, 1440delG. His two affected children were compound heterozygotes for this mutation and a novel missense mutation, G504D, the first putative missense mutation reported in the transmembrane domain of DLL3. Their two unaffected siblings were heterozygotes for the 1440delG mutation. Pseudodominant inheritance has been confirmed, and the findings raise potential consequences for genetic counseling in relation to the SCD disorders.     

Phenotypically dissimilar hypophosphatasia in two sibships.

Autosomal dominant and autosomal recessive forms of hypophosphatasia have been reported; generally the clinical picture runs true to form in families. In each of 2 kindreds, 2 sibs were clinically affected by hypophosphatasia to a markedly different extent. One set of sibs showed the lethal (perinatal) and infantile forms. The other showed the dental and adult forms. In both families there was consanguinity, albeit distant, and clinical expression in sibs supporting autosomal recessive inheritance.     

Phenotypically dissimilar hypophosphatasia in two sibships

Autosomal dominant and autosomal recessive forms of hypophosphatasia have been reported; generally the clinical picture runs true to form in families. In each of 2 kindreds, 2 sibs were clinically affected by hypophosphatasia to a markedly different extent. One set of sibs showed the lethal (perinatal) and infantile forms. The other showed the dental and adult forms. In both families there was consanguinity, albeit distant, and clinical expression in sibs supporting autosomal recessive inheritance.     

Clinical homogeneity and genetic heterogeneity in Weill-Marchesani syndrome

Weill-Marchesani syndrome (WMS) is a rare condition characterized by short stature, brachydactyly, joint stiffness, and characteristic eye abnormalities including microspherophakia, ectopia of lens, severe myopia, and glaucoma. Both autosomal recessive (AR) and autosomal dominant (AD) modes of inheritance have been described for WMS. A locus for AR WMS has recently been mapped to chromosome 19p13.3-p13.2 while mutation within the fibrillin-1 gene (15q21.1) was found in one AD WMS family. In order to answer the question of whether or not genetic heterogeneity could be related to a clinical heterogeneity, we reviewed 128 WMS patients from the literature (including 57 AR, 50 AD, and 21 sporadic cases), with a particular attention to clinical features. Statistical analyses using Fischer exact test were used to compare the proportions of 12 clinical parameters between AR and AD patients. There was no significant difference between both groups for myopia, glaucoma, cataract, short stature, brachydactyly, thick skin, muscular build, and mental retardation. Significant results were found for microspherophakia (94% in AR, 74% in AD, Fischer 0.007), ectopia lentis (64% in AR, 84% in AD, Fischer 0.016), joint limitations (49% in AR, 77% in AD, Fischer 0.010), and cardiac anomalies (39% in AR, 13% in AD, Fischer 0.004). Nevertheless, we failed to distinguish AR from AD inheritance in individual cases. These results support the clinical homogeneity but the genetic heterogeneity of WMS.     

Congenital hypoplastic anemia: Another example of autosomal dominant transmission

Congenital hypoplastic anemia (CHA) or Blackfan-Diamond anemia (BDA) is a rare congenital abnormality of erythropoiesis characterized by normochromic, macrocytic anemia presenting in infancy or early childhood. Associated phenotypic abnormalities such as triphalangeal thumbs and cleft lip and/or palate are found in 70% of cases. Although most cases are sporadic, several reports suggest either autosomal dominant or autosomal recessive inheritance. We report on a 3 generation family with autosomal dominant inheritance of CHA. © 1994 Wiley-Liss, Inc.     

Hyper-IgE syndromes

Summary: The hyper‐immunoglobulin E (IgE) syndromes (HIES) are primary immunodeficiencies characterized by the clinical triad of recurrent staphylococcal abscesses, recurrent cyst‐forming pneumonia, and an elevated serum IgE level of >2000 IU/ml. Most cases are sporadic; however, multiplex families displaying autosomal dominant (AD) and autosomal recessive (AR) inheritance have been described. In most sporadic and AD cases, the HIES clinical triad is part of a multisystem disorder including abnormalities of the soft tissue, skeletal, and dental systems. In contrast, those with AR‐HIES have severe molluscum contagiosum and other viral infections and may develop severe neurological complications. Unlike patients with sporadic HIES and AD‐HIES, those with AR‐HIES lack skeletal or dental involvement and do not develop lung cysts. Additional variants of HIES are discussed in this review. The etiology of HIES is still unresolved. Recent research points toward a skewed T helper 1 (Th1) cell/Th2 cell ratio and the involvement of chemokines. Therapy for HIES is directed at prevention and management of infections by using sustained systemic antibiotics and antifungals along with topical therapy for eczema and drainage of abscesses. Anti‐staphylococcal antibiotic prophylaxis is useful. Interferons, immunoglobulin supplementation, or low‐dose cyclosporine A have been reported to benefit selected patients, but they are not generally indicated.     

Mental retardation with pterygia, shortness and distinct facial appearance A new MCA/MR syndrome

During a systematic survey of the mentally retarded, 3 related females were seen with a similar syndrome of shortness, unusual combination of craniofacial anomalies (trigonocephaly; bulging forehead; flat face; posteriorly angulated, lowset ears and microretrognathia), and genital hypoplasia in all 3 cases, and multiple pterygia in one. The facial changes were also noted in 2 grandmothers and may indicate autosomal dominant inheritance of this presently "private" MCA/MR syndrome.     

In frame fibrillin-1 gene deletion in autosomal dominant Weill-Marchesani syndrome

Weill-Marchesani syndrome (WMS) is a connective tissue disorder characterised by short stature, brachydactyly, joint stiffness, and characteristic eye anomalies including microspherophakia, ectopia of the lenses, severe myopia, and glaucoma. Both autosomal recessive (AR) and autosomal dominant (AD) modes of inheritance have been described and a gene for AR WMS has recently been mapped to chromosome 19p13.3-p13.2. Here, we report on the exclusion of chromosome 19p13.3-p13.2 in a large AD WMS family and show that, despite clinical homogeneity, AD and AR WMS are genetically heterogeneous entities. Because two AD WMS families were consistent with linkage to chromosome 15q21.1, the fibrillin-1 gene was sequenced and a 24 nt in frame deletion within a latent transforming growth factor-beta1 binding protein (LTBP) motif of the fibrillin-1 gene was found in a AD WMS family (exon 41, 5074_5097del). This in frame deletion cosegregated with the disease and was not found in 186 controls. This study strongly suggests that AD WMS and Marfan syndrome are allelic conditions at the fibrillin-1 locus and adds to the remarkable clinical heterogeneity of type I fibrillinopathies.     

Hyperekplexia: pedigree studies in two families

We report on 2 unrelated Japanese families, each with several individuals affected with hyperekplexia, a rare autosomal dominant form of exaggerated startle response of neonatal onset. In the first family, affected relatives included a 4-week-old boy, his mother, grandmother, a maternal uncle, and 2 maternal cousins. In the second family, affected were a 4-week-old boy, his father, and an elder brother. These 9 individuals had various combinations of transient infantile hypertonia and hypokinesia, exaggerated startle response with falling episodes, nocturnal myoclonus and an easily elicited head retraction reflex, hip dislocation, and umbilical hernia. Treatment with clonazepam was effective in relieving these manifestations in the affected infants and children. Genetic analysis of these 2 families and 4 others in the literature suggests autosomal dominant inheritance with considerable variability but complete penetrance. Another 3 families in the literature were reported, suggesting the existence of startle disorder with an autosomal recessive inheritance. A sporadic case is also known, presumably representing a fresh mutation of a dominantly inherited trait.     

Feature of food allergy developed during infancy (1)--relationship between infantile atopic dermatitis and food allergy]

BACKGROUND: Most of food allergy (FA) cases during childhood start as infantile atopic dermatitis (AD) at the ages of a few months old. We tried to clarify the association between infantile AD and FA during infancy. METHODS: We analyzed relationship between AD and FA during infancy among patients with 208 cases, who had visited our outpatient clinic with chief complaint of "eczema" from 1998 to 2000. RESULTS: Among 208 cases, 148 cases (71%) were diagnosed as infantile AD, moreover 109 cases (74%) were diagnosed as FA among infantile AD. The most frequent food antigens among infantile AD were egg (72.3%), cow's milk (39.9%), wheat (12.2%) and soybean (7.4%), respectively, in addition to these food antigens, food allergy was widely recognized against peanuts, sesame, meats, buckwheat, fishes and potato. In terms of food antigen, 44 cases with single food allergy against egg were seen out of 46 single allergy cases, whereas 36 cases with double food allergy against both egg and cow's milk were seen in 63 multiple food allergy cases. Although the value of antigen specific IgE against egg and cow's milk was recognized for the diagnosis of food allergy during infancy, even cases with negative IgE against those foods were proved to be food allergy by food elimination and provocation tests. In contrast to egg and cow's milk, positive IgE against rice, soybean, and wheat did not always correlate with the results of the diagnosis of food allergy. Concerning risk factors of AD, family history of any allergy diseases and passive smoking were recognized in comparison with infantile eczema. Neither the nutrition method nor incomplete elimination of diet during pregnancy and lactation had anything to do with the development of AD. CONCLUSION: When infantile AD cases were not improved by environmental control, skin care and application of steroid ointment, it would be important for doctors to think of the possibility of FA.     

First identification of a gene defect for hypophosphatasia: evidence that alkaline phosphatase acts in skeletal mineralization

Hypophosphatasia is a heritable disorder characterized by defective osteogenesis and deficient liver/bone/kidney alkaline phosphatase (L/B/K ALP) activity. Severe forms of the disease are inherited in an autosomal recessive fashion. We examined cultured skin fibroblasts from twelve patients with severe hypophosphatasia. All were deficient in L/B/K ALP activity, yet produced normal levels of the corresponding mRNA. Sequence analysis of L/B/K ALP cDNA isolated from one of the patient-derived fibroblast lines revealed a point mutation that converted amino acid 162 of mature L/B/K ALP from alanine to threonine. The patient was homozygous and the parents, who are second cousins, heterozygous for this mutation. Introduction of the mutation into an otherwise normal cDNA disrupted the expression of active enzyme, demonstrating that a defect in the L/B/K ALP gene resulted in hypophosphatasia and that the enzyme is, therefore, essential for normal skeletal mineralization.     

Adult hypophosphatasia without apparent skeletal disease: “odontohypophosphatasia“ in four heterozygote members of a family

Summary Twenty members of a family with adult hypophosphatasia were examined clinically and biochemically. Severe caries causing early loss of permanent teeth was the only clinical symptom which could be attributed to hypophosphatasia. None of them had a history of defective bone mineralization, rachitic skeletal alterations, and recurrent pseudofractures or fractures. An iliac crest bone biopsy of the proposita showed a normal finding corresponding to the age of the patient.Four family members in two subsequent generations were affected, thus suggesting an autosomal dominant inheritance. Their serum and leukocyte alkaline phosphatases were reduced. The phosphoethanolamine (PEA) excretion in the urine was increased to a level which suggests a heterozygote state. The serum alkaline phosphatase activity could be ascribed to the liver isoenzyme fraction. This was shown by polyacrylamide electrophoresis, by inhibition studies with organ-specific inhibitors, heat inactivation, inhibition by antibodies, and treatment with neuraminidase.The proposita had an unexplained, diffuse fatty infiltration of the liver. Thus, not only alterations of bone but also of liver metabolism in hypophosphatasia should be considered.The variety of adult hypophosphatasia described in this paper is characterized by the lack of severe bone abnormalities, the apparently autosomal dominant inheritance, and the reduction of bone and intestinal isoenzyme in the serum. Our study suggests that hypophosphatasia is a heterogenous disorder which includes both severe and clinically mild forms.     

First Identification of a Gene Defect for Hypophosphatasia: Evidence That Alkaline Phosphatase Acts in Skeletal Mineralization

Hypophosphatasia is a heritable disorder characteriazed by defective osteogenesis and deficient liver/bone/kidney alkaline phosphatase (L/B/K ALP) activity. Severe forms of the disease are inherited in an autosomal recessive fashion. We examined cultured skin fibroblasts from twelve patients with severe hypophosphatasia. All were deficient in L/B.K ALP activity, yet produced normal levels of the corresponding mRNA. Sequence analysis of L/B/K ALP cDNA isolated from one of the patient-derived fibroblast lines revealed a point mutation that converted amino acid 162 of mature L/B/K ALP from alanine to threonine. The patient was homozygous and the parents, who are second cousins, heterozygous for this mutation. Introduction of the mutation into an otherwise normal cDNA disrupted the expression of active enzyme, demonstrating that a defect in the L/B/K ALP gene resulted in hypophosphatasia and that the enzyme is, therefore, essential for normal skeletal mineralization.     

Family trio-based sequencing in 404 sporadic bilateral hearing loss patients discovers recessive and De novo genetic variants in multiple ways

Hereditary hearing loss (HL) has high genetic and phenotypical heterogeneity including the overlapping and variable phenotypic features. For sporadic HL without a family history, it is more difficult to indicate the contribution of genetic factors to define a pattern of inheritance. We assessed the contribution of genetic variants and patterns of inheritance by a family trio-based sequencing and provided new insight into genetics. We conducted an analysis of data from unrelated sporadic patients with HL (n = 404) who underwent trio-based whole-exome sequencing (trio-WES) or proband-only WES (p-WES) or targeted exome sequencing (TES), and the samples of their unaffected-parents (n = 808)were validated. A molecular diagnosis was rendered for 191 of 404 sporadic HL patients (47.3%) in multiple modes of inheritance, including autosomal recessive (AR), autosomal dominant (AD) caused by de novo variants, copy-number variants (CNVs), X-linked recessive, and dual genetic diagnosis. Among these patients, 83 (43.5%) cases were diagnosed with variants in rare genes. Sporadic HL patients were identified by multiple modes of transmission. Observed variations in rare genes and multiple modes of inheritance can strikingly emphasize the important etiological contribution of recessive and de novo genetic variants to a large cohort of sporadic HL cases plus their parents.