Unilateral vestibular schwannoma and meningiomas in a patient with PIK3CA-related segmental overgrowth: Co-occurrence of mosaicism for 2 rare disorders.

A 28-year-old female with PIK3CA-related segmental overgrowth presented with headaches. She also had a unilateral vestibular schwannoma (VS), as well as 3 small (<2 cm) meningiomas, which according to the Manchester consensus diagnostic criteria for neurofibromatosis 2 (NF2) is sufficient for a clinical diagnosis. Analysis of blood revealed a mosaic PIK3CA c.2740G>A (p.Gly914Arg) mutation, confirming the diagnosis of PIK3CA-related overgrowth, but no mutations in NF2 were detected. Although VS has not previously been reported in PIK3CA-related segmental overgrowth, meningiomas have, raising the question of whether this patient's VS and meningiomas represent coincidental NF2 or phenotypic extension of her overgrowth syndrome. Genetic analysis of the VS revealed a heterozygous NF2 mutation c.784C>T (p.Arg262Ter) and loss of a portion of 22q, including NF2, SMARCB1, and LZTR1 genes. These results suggest that the patient has 2 different mosaic disorders, NF2 and PIK3CA-related overgrowth. The PIK3CA mutation was also present in the VS. Confirmation of the clinical diagnosis of mosaic NF2 in this patient has implications for monitoring and highlights the possibility of co-occurrence of mosaicism for multiple rare disorders in a single patient.

Phenotype analysis impacts testing strategy in patients with Currarino syndrome.

Currarino syndrome (OMIM 175450) presents with sacral, anorectal, and intraspinal anomalies and presacral meningocele or teratoma. Autosomal dominant loss-of-function mutations in the MNX1 gene cause nearly all familial and 30% of sporadic cases. Less frequently, a complex phenotype of Currarino syndrome can be caused by microdeletions of 7q containing MNX1. Here, we report one familial and three sporadic cases of Currarino syndrome. To determine the most efficient genetic testing approach for these patients, we have compared results from MNX1 sequencing, chromosomal microarray, and performed a literature search with analysis of genotype-phenotype correlation. Based on the relationship between the type of mutation (intragenic MNX1 mutations vs 7q microdeletion) and the presence of intellectual disability, growth retardation, facial dysmorphism, and associated malformations, we propose a testing algorithm. Patients with the classic Currarino triad of malformations but normal growth, intellect, and facial appearance should have MNX1 sequencing first, and only in the event of a normal result should the clinician proceed with chromosomal microarray testing. In contrast, if growth delay and/or facial dysmorphy and/or intellectual disability are present, chromosomal microarray should be the first method of choice for genetic testing.

Multiple orbital neurofibromas, painful peripheral nerve tumors, distinctive face and marfanoid habitus: a new syndrome.

Four unrelated patients having an unusual clinical phenotype, including multiple peripheral nerve sheath tumors, are reported. Their clinical features were not typical of any known familial tumor syndrome. The patients had multiple painful neurofibromas, including bilateral orbital plexiform neurofibromas, and spinal as well as mucosal neurofibromas. In addition, they exhibited a marfanoid habitus, shared similar facial features, and had enlarged corneal nerves as well as neuronal migration defects. Comprehensive NF1, NF2 and SMARCB1 mutation analyses revealed no mutation in blood lymphocytes and in schwann cells cultured from plexiform neurofibromas. Furthermore, no mutations in RET, PRKAR1A, PTEN and other RAS-pathway genes were found in blood leukocytes. Collectively, the clinical and pathological findings in these four cases fit no known syndrome and likely represent a new disorder.

High incidence of profound biotinidase deficiency detected in newborn screening blood spots in the Somalian population in Minnesota.

Newborns identified with profound biotinidase deficiency (BTD) by the Minnesota Newborn Screening Program (MN NBS) between 1 October 2004 and 30 May 2008 were all from new immigrant groups. Thirty-three positive cases of BTD were identified out of 264 727 infants screened by the Wolf colorimetric system during the period of this study by MN NBS. Five cases of profound BTD (0.1 to <0.6 nmol/min per ml) and 26 cases of partial BTD (0.9 to 2.3 nmol/min per ml) were later confirmed through measurement of serum biotinidase activity. The incidence of combined partial and profound BTD of 1/8540 and that of profound BTD of 1/52 945 in Minnesota are unusually high in comparison with the reported worldwide numbers of 1/61 067 for combined BTD and 1/137 401 for profound BTD. Four out of the 5 cases of profound BTD ascertained in the MN NBS cohort were of Somali ethnic background, and the remaining case was of Asian (Pakistani/Indian) ethnic background. All four Somali patients have the P497S mutation, with one of the four being homozygous for the mutation. The three compound heterozygotes all have a novel mutation (P142T) and two of them have another change (Y428Y) that has never been described. Within the last two decades, Minnesota has become home to an estimated 40 000 Somali immigrants and their children (<1% of the total Minnesota population). New population demographics prompt careful analysis of case cohorts to identify specific groups at risk for rare inborn errors of metabolism.

NF1 plexiform neurofibroma growth rate by volumetric MRI: relationship to age and body weight.

OBJECTIVE: To longitudinally analyze changes in plexiform neurofibroma (PN) volume in relation to age and body growth in children and young adults with neurofibromatosis type 1 and inoperable, symptomatic, or progressive PNs, using a sensitive, automated method of volumetric MRI analysis. METHODS: We included patients 25 years of age and younger with PNs entered in a natural history study or in treatment trials who had volumetric MRI over > or =16 months. RESULTS: We studied 49 patients (median age 8.3 years) with 61 PNs and a median evaluation period of 34 months (range 18 to 70). The PN growth rates varied among patients, but were constant within patients. Thirty-four patients (69%) experienced > or =20% increase in PN volume during the observation period. PN volume increased more rapidly than body weight over time (p = 0.026). Younger patients had the most rapid PN growth rate. CONCLUSIONS: Volume increase of plexiform neurofibromas is a realistic and meaningful trial endpoint. In most patients plexiform neurofibroma growth rate exceeded body growth rate. The youngest patients had the fastest plexiform neurofibroma growth rate, and clinical drug development should be directed toward this population. Age stratification for clinical trials for plexiform neurofibromas should be considered.

Phase II trial of pirfenidone in adults with neurofibromatosis type 1.

We performed an open-label phase II trial of oral pirfenidone in 24 patients with neurofibromatosis type 1 (NF1). Tumors were monitored by three-dimensional MRI. At the end of treatment, four patients had a decrease in tumor volume by 15% or more, three had tumor progression, and 17 remained stable. Pirfenidone warrants further investigation in NF1, which has until now lacked an effective control therapy.

Connective tissue dysplasia in five new patients with NF1 microdeletions: further expansion of phenotype and review of the literature.

Approximately 5% of patients with neurofibromatosis type 1 (NF1) have deletions of the entire NF1 gene. The phenotype usually includes early onset, large number of neurofibromas, presence of congenital anomalies, cognitive deficiency, and variable dysmorphic features and growth abnormalities. Connective tissue abnormalities are not generally recognised as a part of NF1 microdeletion syndrome, but mitral valve prolapse, joint laxity, and/or soft skin on the palms have been reported in a few patients. We describe clinical findings in six newly diagnosed patients with NF1 microdeletions, five of whom presented with connective tissue abnormalities. A literature review of the clinical findings associated with NF1 microdeletion was also performed. Our report confirms that connective tissue dysplasia is common in patients with NF1 microdeletions. Given the potential for associated cardiac manifestation, screening by echocardiogram may be warranted. Despite the large number (>150) of patients with known NF1 microdeletions, the clinical phenotype remains incompletely defined. Additional reports of patients with NF1 microdeletions, including comprehensive clinical and molecular information, are needed to elucidate possible genotype-phenotype correlation.

Selective antibody immune deficiency in a patient with Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome is a rare autosomal recessive disorder characterized by multiple congenital anomalies and various degrees of cognitive deficits. This condition results from a deficiency of 7-dehydrocholesterol reductase, a critical step in cholesterol biosynthesis. Children with Smith-Lemli-Opitz syndrome have frequent infections, particularly of the respiratory tract. Immunodeficiency, however, is not recognized as a part of this metabolic condition. Frequent infections are usually attributed to a decreased patient mobility and reduced respiratory effort secondary to muscular hypotonia and mental retardation, which are often present in affected individuals. We describe a patient with Smith-Lemli-Opitz syndrome and recurrent respiratory infections who was found to have a selective antibody deficiency. The immunological diagnosis was based on an absent immune response to Pneumovax. She also had no immunological response to hepatitis B vaccine and was unable to break down red cells with isoagglutinin B. Therapy with intravenous IgG (IVIG) was initiated. Infections were less severe, although they still occurred in a high frequency after initiation of the IVIG therapy. This finding prompts the need for a higher index of suspicion for an underlying immune deficiency in patients with Smith-Lemli-Opitz syndrome who present with recurrent and chronic infections. Early recognition and appropriate therapeutic interventions may decrease the severity of infections, prevent potentially fatal infections, and eventually improve the quality of life in these patients.

Haploinsufficiency for one COL3A1 allele of type III procollagen results in a phenotype similar to the vascular form of Ehlers-Danlos syndrome, Ehlers-Danlos syndrome type IV.

Mutations in the COL3A1 gene that encodes the chains of type III procollagen result in the vascular form of Ehlers-Danlos syndrome (EDS), EDS type IV, if they alter the sequence in the triple-helical domain. Although other fibrillar collagen-gene mutations that lead to allele instability or failure to incorporate proalpha-chains into trimers-and that thus reduce the amount of mature molecules produced-result in clinically apparent phenotypes, no such mutations have been identified in COL3A1. Furthermore, mice heterozygous for Col3a1 "null" alleles have no identified phenotype. We have now found three frameshift mutations (1832delAA, 413delC, and 555delT) that lead to premature termination codons (PTCs) in exons 27, 6, and 9, respectively, and to allele-product instability. The mRNA from each mutant allele was transcribed efficiently but rapidly degraded, presumably by the mechanisms of nonsense-mediated decay. In a fourth patient, we identified a point mutation, in the final exon, that resulted in a PTC (4294C-->T [Arg1432Ter]). In this last instance, the mRNA was stable but led to synthesis of a truncated protein that was not incorporated into mature type III procollagen molecules. In all probands, the presenting feature was vascular aneurysm or rupture. Thus, in contrast to mutations in genes that encode the dominant protein of a tissue (e.g., COL1A1 and COL2A1), in which "null" mutations result in phenotypes milder than those caused by mutations that alter protein sequence, the phenotypes produced by these mutations in COL3A1 overlap with those of the vascular form of EDS. This suggests that the major effect of many of these dominant mutations in the "minor" collagen genes may be expressed through protein deficiency rather than through incorporation of structurally altered molecules into fibrils.

Role of common gene variations in the molecular pathogenesis of short-chain acyl-CoA dehydrogenase deficiency.

ABSTRACT Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is considered a rare inherited mitochondrial fatty acid oxidation disorder. Less than 10 patients have been reported, diagnosed on the basis of ethylmalonic aciduria and low SCAD activity in cultured fibroblast. However, mild ethylmalonic aciduria, a biochemical marker of functional SCAD deficiency in vivo, is a common finding in patients suspected of having metabolic disorders. Based on previous observations, we have proposed that ethylmalonic aciduria in a small proportion of cases is caused by pathogenic SCAD gene mutations, and SCAD deficiency can be demonstrated in fibroblasts. Another - much more frequent - group of patients with mild ethylmalonic aciduria has functional SCAD deficiency due to the presence of susceptibility SCAD gene variations, i.e. 625G>A and 511C>T, in whom a variable or moderately reduced SCAD activity in fibroblasts may still be clinically relevant. To substantiate this notion we performed sequence analysis of the SCAD gene in 10 patients with ethylmalonic aciduria and diagnosed with SCAD deficiency in fibroblasts. Surprisingly, only one of the 10 patients carried pathogenic mutations in both alleles, while five were double heterozygotes for a pathogenic mutation in one allele and the 625G>A susceptibility variation in the other. The remaining four patients carried only either the 511C>T or the 625G>A variations in each allele. Our findings document that patients carrying these SCAD gene variations may develop clinically relevant SCAD deficiency, and that patients with even mild ethylmalonic aciduria should be tested for these variations.

Genomic organization of the human phosphomannose isomerase (MPI) gene and mutation analysis in patients with congenital disorders of glycosylation type Ib (CDG-Ib).

CDG-Ib is the "gastro-intestinal" type of the congenital disorders of glycosylation (CDG) and a potentially treatable disorder. It has been described in patients presenting with congenital hepatic fibrosis and protein losing enteropathy. The symptoms result from hypoglycosylation of serum- and other glycoproteins. CDG-Ib is caused by a deficiency of mannose-6-phosphate isomerase (synonym: phosphomannose isomerase, EC 5.3.1.8), due to mutations in the MPI gene. We determined the genomic structure of the MPI gene in order to simplify mutation detection. The gene is composed of 8 exons and spans only 5 kb. Eight (7 novel) different mutations were found in seven patients with a confirmed phosphomannose isomerase deficiency, analyzed in the context of this study: six missense mutations, a splice mutation and one insertion. In the last, the mutation resulted in an unstable transcript, and was hardly detectable at the mRNA level. This emphasizes the importance of mutation analysis at the genomic DNA level.

Characteristics of two cases with dup(15)(q11.2-q12): one of maternal and one of paternal origin.

PURPOSE: The phenotype correlations for interstitial duplications that include the Prader-Willi/Angelman syndrome critical region are not well established. We describe two such duplication cases, one of which was of maternal origin and the other was paternal. METHODS: High resolution G-banding, fluorescence in situ hybridization (FISH) for SNRP-N and D15S10 were used for cytogenetic analysis. Southern blot analyses based on parent of origin specific DNA methylation at D15S63 (PW71) locus were utilized for detection of methylated and unmethylated fragments. RESULTS: The duplication was established by the FISH analysis. The molecular pattern suggested a maternal origin of the duplication in patient 1 and a paternal origin in patient 2. Patient 1 (2 years old) had developmental and speech delays with pervasive developmental disorder or mild autism, strabismus, and normal growth parameters with seizures. Patient 2 (16 years old) had global developmental delay, verbal IQ of 94, depression, obesity, food-seeking behavior, and significant behavioral problems that included self-injurious tendencies. Neither patient had significant dysmorphic features or abnormalities of internal organs. CONCLUSION: The two cases suggest that some patients with 15q11.2q12 duplication may have significant anomalies, and there appear to be phenotypic differences between maternal and paternal transmission of the duplication.

Severe hypoglycemia as a presenting symptom of carbohydrate-deficient glycoprotein syndrome.

We describe clinical, biochemical, and molecular findings in a 2(1/2)-year-old girl with a phosphomannose isomerase deficiency who presented with severe and persistent hypoglycemia and subsequently developed protein-losing enteropathy, liver disease, and coagulopathy. Six months of therapy with mannose supplementation resulted in clinical improvement and partial correction of biochemical abnormalities.

Mannose-binding lectin deficiency associated with neutrophil chemotactic unresponsiveness to C5a.

BACKGROUND: Mannose-binding lectin (MBL) plays an important role in host defense by activating the complement cascade. OBJECTIVE: Three children with a history of recurrent infections since infancy were found to have MBL deficiency associated with a neutrophil chemotactic unresponsiveness specific to C5a. We have studied the genomic sequence of the C5a receptor (C5aR) in 2 of the subjects to determine whether this unresponsiveness was due to a genetic mutation or to aberrant complement activation associated with the MBL deficiency. METHODS: MBL genotype analysis was performed by PCR-based methods with use of specific primers and restriction enzymes to detect the 3 previously reported mutations. Expression of C5aR was analyzed by flow cytometry. The C5aR gene was amplified from the patient's genomic DNA by PCR and sequenced by standard procedures. RESULTS: C5aR was found to be expressed normally on the neutrophils of one of the subjects. Sequence analysis of the C5aR gene revealed a point mutation that substituted threonine at position 261 for alanine in one patient but no abnormality in the other, suggesting gene polymorphism. Treatment of 2 patients with granulocyte-colony stimulating factor corrected the neutrophil chemotactic abnormality in vitro and induced a significant clinical improvement. CONCLUSION: MBL deficiency can be associated with neutrophil chemotactic unresponsiveness to C5a and it is clinically manifested by recurrent and chronic infections. Treatment of these patients with granulocyte colony-stimulating factor results in normalization of neutrophil chemotaxis against C5a and significant clearing of infections.

Guidelines for buccal smear collection in breast-fed infants.

Buccal smear analysis is a noninvasive, fast, and relatively inexpensive diagnostic method. It is used commonly where rapid gender identification is necessary or, more recently, for detection of aneusomy, microdeletion syndromes, and a variety of polymerase chain reaction-based molecular genetic tests. Previously we have shown that maternal cells can contaminate buccal smears taken from breast-fed infants, resulting in difficulty with test interpretation. The aim of this study was to determine optimal timing and technique for buccal smear collection in breast-fed infants in order to avoid diagnostic errors. We analyzed prospectively 50 breast-fed male infants for presence of cells with XX signal pattern from buccal mucosa scrapings at different times after breast feeding. The efficiency of mucosal cleaning on elimination of maternal cells was evaluated by comparing the proportion of XX cells before and after wiping of buccal mucosa with a cotton swab. Maternal cells were present in 23 of 48 (47.9%) samples collected within 5 min of feeding. The proportion of XX signal pattern was significantly (P = 0.001) reduced in samples collected at 30 min (8/48, P = 0.001) and > or =60 min (2/29, P = 0.0002) after feeding. Mucosal cleaning prior to smear collection significantly decreased the number of XX positive samples from 23 of 48 to 10 of 48 (P = 0.002). Buccal smears should not be obtained in nursing neonates until at least 60 min after breast feeding. In addition, prior to sample collection, buccal mucosa should be cleaned thoroughly with a cotton swab applicator. The same guidelines are applicable to older nursing infants.

Mannose-binding lectin (MBL) deficiency. Variant alleles in a midwestern population of the United States.

OBJECTIVES: To describe a method for the genotype analysis of mutations in the gene encoding mannose binding lectin (MBL), study the incidence of MBL gene mutations in a population of the Midwest of the United States, and compare it with previous reports in other populations. The objective of this report is also an extensive review of the literature to analyze the importance of MBL deficiency in human disease. DATA SOURCES: Blood samples were obtained from the blood bank of the Mayo Clinic. They represented a population of blood donors living in the Midwest of the United States. A review of the literature was performed by selection of articles from Medline database. STUDY SELECTION: Blood samples, 148, were randomly selected from a pool of blood donors. They included both females and males. Blood donors had been previously screened by a questionnaire and were found to be generally healthy. For the literature review, articles containing original data on MBL in humans were selected. RESULTS: Forty-five (30.4%) of the analyzed blood donors carried one variant allele, while 8 donors (5.4%) showed homozygosity or compound heterozygosity for MBL gene mutations. Allele frequency for the different MBL variants is provided. Our results are similar to those reported for the Danish population. Literature review provides evidence for a significant role of MBL deficiency in the innate immunity. The incidence of MBL mutations is higher among patients with recurrent infections and autoimmune disorders. CONCLUSIONS: Mannose binding lectin deficiency has a definite role in the pathogenesis of primary immunodeficiency in humans and screening patients with recurrent infections and autoimmunity might be beneficial. The significance of MBL deficiency among apparently healthy blood donors remains to be determined.

Familial occurrence of carcinoid tumors and association with other malignant neoplasms.

Carcinoid tumors are generally thought to be sporadic, except for a small proportion that occur as a part of multiple endocrine neoplasia syndromes. Data regarding the familial occurrence of carcinoid as well as its potential association with other neoplasms are limited. A chart review was conducted on patients indexed for malignant carcinoid tumor of the gastrointestinal tract seen at the Mayo Clinic between 1988 and 1996. A survey of family history of malignancies and personal history of other tumors was mailed to all eligible patients. Data for 245 patients were analyzed. Observed rates of carcinoids and other malignancies were compared with Surveillance, Epidemiology, and End Results data. Estimates of the cumulative probability for first-degree relatives developing a carcinoid tumor were calculated. Nine (3.7%) patients with carcinoid tumor had at least one first-degree relative with the same malignancy. The rate of carcinoid tumor in first-degree relatives of probands was higher (P < 0.0001) than expected based on the Surveillance, Epidemiology, and End Results population data. Cumulative probability in a first-degree relative for developing a carcinoid was calculated to be 1.5% at age 80. There was an increased risk for developing a carcinoid tumor among first-degree relatives of patients with carcinoid. Neither patients with carcinoid nor their first-degree relatives had an increased incidence of other malignancies.

Visual impairment due to macular disciform scars in a 20-year-old man with Smith-Magenis syndrome: another ophthalmologic complication.

We describe a 20-year-old man with Smith-Magenis syndrome and a 46,XY,del(17)(p11.2p11.2) karyotype. The interstitial deletion was confirmed by metaphase analysis using the fluorescent in situ hybridization probe (D17S29) for the Smith-Magenis region. The patient had hypertelorism, exotropia, and high myopia. Examination under anesthesia showed a lacquer crack near the right macula and a disciform scar of the left macula. Six months later, the patient presented with subacute visual loss. Examination demonstrated end-stage macula degeneration with bilateral disciform scars. There was no evidence of retinal detachment. Prior reports of Smith-Magenis syndrome mention telecanthus, ptosis, strabismus, iris anomalies, cataract, microcornea, optic nerve hypoplasia, myopia, retinal detachment, and lattice retinal degeneration. Bilateral macular degeneration has not been reported previously, and it may be an additional ophthalmologic manifestation of Smith-Magenis syndrome, either as a primary manifestation or as a direct consequence of high myopia.