Endocrine abnormalities in Townes-Brocks syndrome.

Townes-Brocks syndrome is a recognizable variable pattern of malformation caused by mutations to the SALL1 gene located on chromosome 16q12.1. Only three known cases of Townes-Brocks syndrome with proven SALL1 gene mutation and concurrent endocrine abnormalities have been previously documented to our knowledge [Kohlhase et al., 1999; Botzenhart et al., 2005; Choi et al., 2010]. We report on two unrelated patients with Townes-Brocks syndrome who share an identical SALL1 mutation (c.3414_3415delAT), who also have endocrine abnormalities. Patient 1 appears to be the first known case of growth hormone deficiency, and Patient 2 extends the number of documented mutation cases with hypothyroidism to four. We suspect endocrine abnormalities, particularly treatable deficiencies, may be an underappreciated component to Townes-Brocks syndrome.

Delineation of a deletion region critical for corpus callosal abnormalities in chromosome 1q43-q44.

Submicroscopic deletions involving chromosome 1q43-q44 result in cognitive impairment, microcephaly, growth restriction, dysmorphic features, and variable involvement of other organ systems. A consistently observed feature in patients with this deletion are the corpus callosal abnormalities (CCAs), ranging from thinning and hypoplasia to complete agenesis. Previous studies attempting to delineate the critical region for CCAs have yielded inconsistent results. We conducted a detailed clinical and molecular characterization of seven patients with deletions of chromosome 1q43-q44. Using array comparative genomic hybridization, we mapped the size, extent, and genomic content of these deletions. Four patients had CCAs, and shared the smallest region of overlap that contains only three protein coding genes, CEP170, SDCCAG8, and ZNF238. One patient with a small deletion involving SDCCAG8 and AKT3, and another patient with an intragenic deletion of AKT3 did not have any CCA, implying that the loss of these two genes is unlikely to be the cause of CCA. CEP170 is expressed extensively in the brain, and encodes for a protein that is a component of the centrosomal complex. ZNF238 is involved in control of neuronal progenitor cells and survival of cortical neurons. Our results rule out the involvement of AKT3, and implicate CEP170 and/or ZNF238 as novel genes causative for CCA in patients with a terminal 1q deletion.

Clinical and mutational spectrum of neurofibromatosis type 1-like syndrome.

CONTEXT: Autosomal dominant inactivating sprouty-related EVH1 domain-containing protein 1 (SPRED1) mutations have recently been described in individuals presenting mainly with café au lait macules (CALMs), axillary freckling, and macrocephaly. The extent of the clinical spectrum of this new disorder needs further delineation. OBJECTIVE: To determine the frequency, mutational spectrum, and phenotype of neurofibromatosis type 1-like syndrome (NFLS) in a large cohort of patients. DESIGN, SETTING, AND PARTICIPANTS: In a cross-sectional study, 23 unrelated probands carrying a SPRED1 mutation identified through clinical testing participated with their families in a genotype-phenotype study (2007-2008). In a second cross-sectional study, 1318 unrelated anonymous samples collected in 2003-2007 from patients with a broad range of signs typically found in neurofibromatosis type 1 (NF1) but no detectable NF1 germline mutation underwent SPRED1 mutation analysis. MAIN OUTCOME MEASURES: Comparison of aggregated clinical features in patients with or without a SPRED1 or NF1 mutation. Functional assays were used to evaluate the pathogenicity of missense mutations. RESULTS: Among 42 SPRED1-positive individuals from the clinical cohort, 20 (48%; 95% confidence interval [CI], 32%-64%) fulfilled National Institutes of Health (NIH) NF1 diagnostic criteria based on the presence of more than 5 CALMs with or without freckling or an NF1-compatible family history. None of the 42 SPRED1-positive individuals (0%; 95% CI, 0%-7%) had discrete cutaneous or plexiform neurofibromas, typical NF1 osseous lesions, or symptomatic optic pathway gliomas. In the anonymous cohort of 1318 individuals, 34 different SPRED1 mutations in 43 probands were identified: 27 pathogenic mutations in 34 probands and 7 probable nonpathogenic missense mutations in 9 probands. Of 94 probands with familial CALMs with or without freckling and no other NF1 features, 69 (73%; 95% CI, 63%-80%) had an NF1 mutation and 18 (19%; 95% CI, 12%-29%) had a pathogenic SPRED1 mutation. In the anonymous cohort, 1.9% (95% CI, 1.2%-2.9%) of individuals with the clinical diagnosis of NF1 according to the NIH criteria had NFLS. CONCLUSIONS: A high SPRED1 mutation detection rate was found in NF1 mutation-negative families with an autosomal dominant phenotype of CALMs with or without freckling and no other NF1 features. Among individuals in this study, NFLS was not associated with the peripheral and central nervous system tumors seen in NF1.

Phakomatosis pigmentovascularis: Implications for severity with special reference to Mongolian spots associated with Sturge-Weber and Klippel-Trenaunay syndromes.

In 1947 the term phakomatosis pigmentovascularis (PPV) was coined to represent the association of widespread, aberrant, and persistent nevus flammeus and pigmentary abnormalities. Four types of PPV have been recognized with type II (nevus flammeus and Mongolian spots) being the most common. Most early cases were of Asian or African descent. Many cases were subsequently associated with Sturge-Weber (S-W) and Klippel-Trenaunay (K-T) syndromes. Almost no literature reports have appeared in the genetic or dysmorphology literature! We present six cases of PPV in which five were either African, Asian or Hispanic, and five of six had an admixture of K-T and S-W. Four had macrocephaly, and one had microcephaly. Four had CNS abnormalities (three with hydrocephalus, one with Arnold-Chiari and one with polymicrogyria), three had mental retardation, and one had seizures. One each had thumb hypoplasia, hydronephrosis, glaucoma, coronal synostosis, and 3-4 finger syndactyly. It is our suspicion and hypothesis that in the presence of persistent, extensive and aberrant Mongolian spots, vascular abnormalities as are seen in K-T and S-W carry a worse prognosis. This may be particularly true either of children of Asian, Hispanic or African heritage or any individuals from darker pigmented skin groups.

A case of myelodysplastic syndrome with acquired monosomy 7 in a child with a constitutional t(1;19) and a mosaicism for trisomy 21.

A 3-year-old patient presented with anemia, thrombocytopenia, and blasts in the peripheral blood. A bone marrow aspirate revealed a myelodysplastic syndrome (MDS). A mosaic abnormal female karyotype 46,XX, t(1;19)(q42; p13.1)c[12]/ 47,idem,+21c[3]/ 47,idem,-7,+21c,+mar[7] was obtained on G-banded metaphases from unstimulated bone marrow aspirate cell culture. To rule out constitutional abnormalities, we performed a cytogenetic analysis on the patient's phytohemagglutinin-stimulated peripheral blood and cultured skin fibroblasts. A karyotype of 46,XX,t(1;19) (q42;p13.1)c was found in all 20 peripheral lymphocytes analyzed, confirming the constitutional origin of the translocation. In addition, 5 out of 50 cells from two separate cultures of the skin fibroblasts contained an extra chromosome 21. The presence of two cell lines in multiple cultures indicates that the patient is a true low-level mosaic for trisomy 21. Because of the finding of monosomy 7 and a marker chromosome only in the trisomy 21 clone, we conclude that the leukemic clone arose from a hematopoietic precursor with constitutional trisomy 21. It is also possible that the t(1;19) played some role in the development of the MDS. Because acute myelogenous leukemia (AML) and MDS with Down syndrome (DS) have distinct biologic and clinical features, the identification of DS patients with a mild or normal phenotype in the AML/MDS population is of fundamental importance for clinical diagnosis and management.