Unique presentation of cutis laxa with Leigh-like syndrome due to ECHS1 deficiency.

Clinical finding of cutis laxa, characterized by wrinkled, redundant, sagging, nonelastic skin, is of growing significance due to its occurrence in several different inborn errors of metabolism (IEM). Metabolic cutis laxa results from Menkes syndrome, caused by a defect in the ATPase copper transporting alpha (ATP7A) gene; congenital disorders of glycosylation due to mutations in subunit 7 of the component of oligomeric Golgi (COG7)-congenital disorders of glycosylation (CDG) complex; combined disorder of N- and O-linked glycosylation, due to mutations in ATPase H+ transporting V0 subunit a2 (ATP6VOA2) gene; pyrroline-5-carboxylate reductase 1 deficiency; pyrroline-5-carboxylate synthase deficiency; macrocephaly, alopecia, cutis laxa, and scoliosis (MACS) syndrome, due to Ras and Rab interactor 2 (RIN2) mutations; transaldolase deficiency caused by mutations in the transaldolase 1 (TALDO1) gene; Gerodermia osteodysplastica due to mutations in the golgin, RAB6-interacting (GORAB or SCYL1BP1) gene; and mitogen-activated pathway (MAP) kinase defects, caused by mutations in several genes [protein tyrosine phosphatase, non-receptor-type 11 (PTPN11), RAF, NF, HRas proto-oncogene, GTPase (HRAS), B-Raf proto-oncogene, serine/threonine kinase (BRAF), MEK1/2, KRAS proto-oncogene, GTPase (KRAS), SOS Ras/Rho guanine nucleotide exchange factor 2 (SOS2), leucine rich repeat scaffold protein (SHOC2), NRAS proto-oncogene, GTPase (NRAS), and Raf-1 proto-oncogene, serine/threonine kinase (RAF1)], which regulate the Ras-MAPK cascade. Here, we further expand the list of inborn errors of metabolism associated with cutis laxa by describing the clinical presentation of a 17-month-old girl with Leigh-like syndrome due to enoyl coenzyme A hydratase, short chain, 1, mitochondria (ECHS1) deficiency, a mitochondrial matrix enzyme that catalyzes the second step of the beta-oxidation spiral of fatty acids and plays an important role in amino acid catabolism, particularly valine.

Phenotype and genotype in 101 males with X-linked creatine transporter deficiency.

BACKGROUND: Creatine transporter deficiency is a monogenic cause of X-linked intellectual disability. Since its first description in 2001 several case reports have been published but an overview of phenotype, genotype and phenotype--genotype correlation has been lacking. METHODS: We performed a retrospective study of clinical, biochemical and molecular genetic data of 101 males with X-linked creatine transporter deficiency from 85 families with a pathogenic mutation in the creatine transporter gene (SLC6A8). RESULTS AND CONCLUSIONS: Most patients developed moderate to severe intellectual disability; mild intellectual disability was rare in adult patients. Speech language development was especially delayed but almost a third of the patients were able to speak in sentences. Besides behavioural problems and seizures, mild to moderate motor dysfunction, including extrapyramidal movement abnormalities, and gastrointestinal problems were frequent clinical features. Urinary creatine to creatinine ratio proved to be a reliable screening method besides MR spectroscopy, molecular genetic testing and creatine uptake studies, allowing definition of diagnostic guidelines. A third of patients had a de novo mutation in the SLC6A8 gene. Mothers with an affected son with a de novo mutation should be counselled about a recurrence risk in further pregnancies due to the possibility of low level somatic or germline mosaicism. Missense mutations with residual activity might be associated with a milder phenotype and large deletions extending beyond the 3' end of the SLC6A8 gene with a more severe phenotype. Evaluation of the biochemical phenotype revealed unexpected high creatine levels in cerebrospinal fluid suggesting that the brain is able to synthesise creatine and that the cerebral creatine deficiency is caused by a defect in the reuptake of creatine within the neurones.

A 1q44 deletion, paternal UPD of chromosome 2 and a deletion due to a complex translocation detected in children with abnormal phenotypes using new SNP array technology.

Children with intellectual disability, dysmorphic features, malformations and/or growth abnormalities frequently display normal karyotypes. Recent studies have shown that genome-wide single nucleotide polymorphism (SNP) arrays can be effective in detecting abnormalities involving copy number variation (CNV), deletions, duplications and loss of heterozygosity (LOH) that routine cytogenetic tests fail to identify. Five patients with various degrees of intellectual disability and/or dysmorphic features and other malformations were whole-genome genotyped using the Human-1 Genotyping BeadChip--Exon-Centrix 100K SNP arrays (Illumina). All patients had undergone routine cytogenetic testing; four patients had normal karyotypes, while one patient had an apparently balanced complex translocation involving chromosomes 1q25, 1q32, 2q23, 7q22 and 16q24. We detected deletions on chromosome 1q44 and 13q31.1 in one patient, and LOH of the entire chromosome 2 in another patient, both with cytogenetically normal karyotypes. The patient with the complex translocation had a deletion on chromosome 7q22.2-22.3, which is in conjunction with one of the translocation breakpoints. Our findings provide further evidence of there being a critical region for the development of microcephaly and corpus callosum abnormalities in children with distal 1q deletions. We have also shown that apparently balanced complex translocations might not be balanced at the DNA level, and we report the fourth case of paternal uniparental disomy of chromosome 2. The results of this study suggest that it may be desirable to investigate idiopathic mental retardation using genome-wide SNP arrays, in conjunction with other cytogenetic and molecular techniques.

Detection of treatable neonatal liver disease by expanded newborn screening.

Two neonates were identified at age 48 h by expanded newborn screening, with abnormal methionine and tyrosine concentrations, which were confirmed on repeat samples. Evidence of previously unsuspected liver disease was found at recall, and there was radiological and biochemical evidence of severe liver disease with hepatic synthetic failure. After inborn errors of metabolism (IEMs) were excluded, both were considered to have neonatal haemochromatosis, on the basis of raised ferritin, iron saturation, and very high α-fetoprotein and confirmed by a mildly hyperferritinaemic sibling in the first case, and raised ferritin and iron saturation in the second. However, it was not feasible to obtain tissue confirmation as the requirement for early therapy precluded biopsy. The babies were treated with antioxidants and iron-chelating agents, and the coagulopathy and hypoalbuminaemia were corrected. Both made a complete recovery and remain well after follow-up. Newborn screening programmes could consider advising clinicians, when tyrosine and methionine values are elevated, that once IEMs are excluded liver disease from other causes must be sought. Neonatal haemochromatosis is an example of one such disease that is potentially treatable.

Familial 22q11.2 duplication: a three-generation family with a 3-Mb duplication and a familial 1.5-Mb duplication.

We report two familial cases of 22q11.2 duplication detected using multiplex ligation-dependent probe amplification (MLPA). In the first case, eight individuals from a three-generation family were found to carry a 3-Mb 22q11.2 duplication. The individuals carrying the duplication show phenotypic variation. This phenotypic variation includes heart defect (1 in 8 individuals, 1/8), submucous cleft palate (2/8), intellectual disability (2/8), speech delay (2/8), behaviour problems (3/8) and brachydactyly (3/8). In the second case, a 1.5-Mb 22q11.2 duplication was detected in a neonate and her normal mother. The neonate presented with severe laryngomalacia causing intermittent stridor. Cranial ultrasound showed small subependymal cysts bilaterally. There was no heart defect or cleft palate, her chest X ray and renal ultrasound were normal. Review at 2 months of age revealed normal growth and development. Our findings broaden the understanding of 22q11.2 duplication syndrome and demonstrate that MLPA is sensitive for detection and sizing of 22q11.2 microduplications.