A homozygote TREX1 mutation in two siblings with different phenotypes: Chilblains and cerebral vasculitis

Three prime repair exonuclease 1 degrades single and double stranded DNA with 3′-5′ nuclease activity and its mutations are related to type 1 IFN mediated autoinflammation due to accumulated intracellular nucleic acids. To date, several cases of systemic lupus erythematosus, Aicardi-Goutieres syndrome, familial chilblain lupus, retinal vasculopathy-cerebral leukodystrophy have been reported with TREX1 mutations.Chilblain lupus is a skin disease characterized by blue-reddish coloring, swelling or ulcers on acral regions of body such as fingertips, heels, nose and auricles. Central nervous system vasculitis is a prominent cause of childhood strokes.10 families with familial chilblain lupus related to TREX1 mutations were reported previously in the literature, in which homozygote D18N variant in TREX1 gene was related to chilblains with cerebral vasculitis.In this report, whole-exome-sequencing revealed a homozygote R114C mutation in TREX1 gene was shown in two siblings with recurrent chilblains whom one of them was the second case accompanied by cerebral vasculitis in the literature. As a result, the approach of WES in clinical use revealed a novel mutation in clinically heterogenous patients to provide genetic counseling.     

Two families with Wilson disease in which siblings showed different phenotypes

We investigated two families with Wilson disease in which siblings showed different clinical phenotypes and different ages at onset. In Family 1, the second and fourth male children demonstrated onset of the neurological type of Wilson disease at 16 and 28 years of age, respectively, and the first female child developed the hepatic type at 38 years of age. In Family 2, the second male child showed neurological symptoms at 32 years of age and was diagnosed as having the hepatoneurological type of Wilson disease; then the 35-year-old first female child was found to have the hepatic type by familial screening. We performed mutation analysis of the ATP7B gene for these patients, and found that the mutation was a compound heterozygote in both families. Previous reports of siblings with Wilson disease have shown an identical clinical phenotype and similar ages at onset. In addition, hepatic-type cases generally occur at lower ages compared with the neurological type. In the present investigation, however, younger patients showed neurological symptoms earlier than their older siblings, and clinical phenotypes differed among siblings in both families. These cases appear to be rare. Individual differences in copper accumulation in hepatic cells and intolerance to copper toxicity might be the reason for this phenomenon. Furthermore, there might be a difference in the dominance of the allele expressing ATP7B protein among these cases, resulting in different clinical phenotypes, because all patients of both families were found to be compound heterozygotes. Received: May 9, 2002 / Accepted: July 19, 2002     

Identification of a novel mutation (867delA) in the glucose-6-phosphatase gene in two siblings with glycogen storage disease type Ia with different phenotypes

We identified a novel mutation (867delA) in the glucose-6-phosphatase gene of two siblings with glycogen storage disease type Ia. Although both siblings share the same mutations, their phenotype regarding adult height and hepatomegaly differs. In glycogen storage disease type Ia, substantial heterogeneity in phenotype is observed. So far, no evidence for a clear genotype-phenotype correlation has been found. Hum Mutat 15:381, 2000.     

Townes-Brocks syndrome with craniosynostosis in two siblings

This report describes a novel truncating c.709C > T p.(Gln237*) SALL1 variant in two siblings exhibiting sagittal craniosynostosis as a unique feature of Townes-Brocks syndrome (TBS, OMIM #107480). TBS is a rare autosomal dominant syndrome with variable phenotypes, including anorectal, renal, limb, and ear abnormalities, which results from heterozygous variants in the SALL1 gene, predominantly located in the 802 bp “hot spot region” within exon 2. Recent studies have suggested that aberrations in primary cilia and sonic hedgehog signalling contribute to the TBS phenotypes. The presence of the novel c.709C > T p.(Gln237*) SALL1 variant was confirmed in both the siblings and their father, whereas no mutations currently associated with craniosynostosis were detected. We hypothesise that the truncating c.709C > T p.(Gln237*) SALL1 variant, which occurs outside the “hot spot region” and inside the glutamine-rich domain coding region, could interfere with ciliary signalling and mechanotransduction, contributing to premature fusion of calvarial sutures. This report broadens the genetic and phenotypic spectrum of TBS and provides the first clinical evidence of craniosynostosis as a novel feature of the syndrome.     

Familial hypertryptophanemia in two siblings

Mild and moderate mental retardation with exaggerated affective responses, periodic mood swings, and apparent hypersexual behavior were present in two siblings with hypertryptophanemia and tryptophanuria. In addition, the male had severe myopia, a speech impediment, musculo-skeletal abnormalities and perceptual hypersensitivity. His sister was deaf, which was ascribed to antenatal rubella. The occurrence in siblings and the presence of abnormal urinary tryptophan metabolites in the mother and a half-sibling suggest that the condition results from an autosomal recessive gene with minor expression in some heterozygotes.     

Generalized arterial calcification of infancy: different clinical courses in two affected siblings

Generalized arterial calcification of infancy (GACI) is a rare autosomal recessive disease caused by mutations in ENPP1. Due to extensive calcification of the arterial media associated with intimal proliferation leading to vascular occlusion, most affected children die within the first 6 months of life. We report on two Taiwanese siblings with an identical genotype, but different clinical course. The male sibling developed heart failure and severe hypertension, and died at the age of 6 weeks despite of treatment with bisphosphonates, ACE inhibitors, and hydralazine. The subsequent female, who was monitored closely pre- and post-natally, is having an uncomplicated clinical course up to the age of 1(1/2) year now. There were similar characteristic sonographic and roentgenographic findings in both siblings in early infancy. In both siblings, the same compound heterozygous mutations (c.1025G > T [p.Gly342Val] and c.1112A > T [Tyr371Phe]) in ENPP1 were identified. Despite the same genotype and similar sonographic and radiographic features in early infancy, the phenotype of GACI can vary to a great extent within one family.     

HLA antigens in two siblings with autoimmune Addison's disease

The diagnosis of autoimmune Addison's disease was established in two siblings by demonstration of serum antibodies against adrenal cortex antigen, elevated P-ACTH combined with a low P-cortisol, and the absence of P-cortisol response to exogenous ACTH. HLA typing in the two siblings and their parents revealed the same HLA phenotype in the two patients. This is compatible with an autosomal recessive mode of inheritance and indicates that a supposed trait for autoimmune Addison's disease may segregate with the HLA complex in the familial form of autoimmune Addison's disease.     

Wolcott-Rallison syndrome in two siblings with isolated central hypothyroidism

Two sibs with an infantile onset of hyperglycemia, recurrent hepatitis, renal insufficiency, developmental delay, and skeletal epiphyseal dysplasia are described. Clinical presentation and radiological features are suggestive of Wolcott-Rallison syndrome, a rare autosomal recessive disease. In both of our cases we found evidence of central hypothyroidism, which appears to be an associated feature of this syndrome. Hypothyroidism should be suspected and screened for in all cases of Wolcott-Rallison syndrome.     

Early-onset stroke in two siblings with Neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder, characterized by cafe-au-lait macules, benign neurofibromas as well as malignant peripheral nerve sheath tumours, freckling in the axillary or inguinal regions, optic glioma and Lisch nodules (iris hamartomas) and further manifestations like bone deformities etc.Additionally, NF1 patients are at increased risk of early-onset cerebrovascular diseases, the pathogenesis of which has not been clarified yet.Here we report the first case of two siblings with NF1 who suffered an acute ischemic stroke.Professionals treating NF1 patients should be aware of the elevated risk of stroke in this population. Large prospective studies are needed to establish optimal guidelines for diagnosis, monitoring and treatment of cerebrovascular disease in patients suffering from NF1, as well as to achieve a consensus on routine vascular screening in NF1.     

Mother and two siblings with cockroach asthma]

We report 2 siblings, an 11 year-old girl and a 10 year-old boy, with cockroach asthma who developed the symptoms in May and October, 1999, respectively. Both children were considered as psychogenic asthma because of poor familial environment and late onset. Their mother also had asthmatic attacks since September, 2001. It became clear in the detailed clinical history that their rooms had not been cleaned up at all for a long period, and a lot of cockroaches had lived in the house. A significantly high titer of cockroach specific IgE-antibody (CAP-RAST) was detected in all three patients, and cockroach was considered as the main allergen of asthma in these patients. Although many cases with cockroach allergy including asthma have been reported in United States, it has not been recognized well in Japan yet. We would like to emphasize that cockroach should be kept in one' s mind as an important allergen of asthma.     

Trisomy 18 mosaicism in two siblings

Two siblings are presented displaying low Girth weight, marked microcephaly, severe mental and growth retardation, and convulsive disorder. Leukocyte and fibroblast cultures showed two cell lines, 46/ 47 ,+ 18 , The extra E group chromosome in 30 to 40% of the cells was identified as No. 18 by Q-banding and G-banding techniques.     

Hereditary spastic diplegia with mental retardation in two young siblings

Two young siblings with hereditary spastic diplegia and mental retardation (Böök's syndrome) have had detailed clinical investigations since infancy. The inheritance pattern of this syndrome in the present family fits well with an autosomal recessive trait - with affected sibs of opposite sex, born to consanguineous healthy parents.     

Fragile X syndrome in two siblings with major congenital malformations

We report on 2 brothers with both fragile X and VACTERL-H syndrome. The first sibling, age 5, had bilateral cleft lip and palate, ventricular septal defect, and a hypoplastic thumb. The second sibling, are 2½, had a trachesophageal fistula, esophageal atresia, and vertebral abnormality. High-resolution chromosome analysis showed a 46, XY chromosome constitution in both siblings. By PCR and Southern blot analysis, the siblings were found to have large triplet repeat expansions in the fragile X gene (FMR 1) and both had methylation mosaicism. Enzyme kinetic studies of iduronate sulfatase demonstrated a two-fold increase in activity in the first sib as compared to the second. Possible mechanisms through which the fragile X mutation can cause down-regulation of adjacent loci are discussed. © 1996 Wiley-Liss, Inc.     

Identification of two different genetic mutation associated with silent phenotypes for human serum cholinesterase in Japanese]

Two different gene mutations associated with the silent phenotype for human serum cholinesterase were demonstrated. DNA from five individuals with silent gene phenotype of three unrelated Japanese families was amplified by the polymerase chain reaction (PCR) and analyzed by direct sequencing. The first instance demonstrated a G----C transversion at codon 365 from GGA (Gly) to CGA (Arg), which was seen in three individuals of the two families. This mutation was resulted to create a new Taq 1 restriction site (TCGA). The second mutation was shown by a double heterozygous condition with two different silent gene mutations in two members of remaining one family. These mutations were as follows: 1) one type was a frameshift mutation, in which an extra A was inserted in codon 315 (ACC----AACC) to create a new stop codon at position 322 and 2) the other was the same point mutation at codon 365 as seen in the first instance. These results indicated that many silent variants can be distinguished by direct sequence analyses of genomic DNA.