Ambiguous Genitalia: An Unexpected Diagnosis in a Newborn.

Alterations in gonad formation or function can lead to congenital conditions in which chromosomal, gonadal, or anatomical sex is atypical. These conditions are referred to as disorders of sex development (DSD) and have a heterogeneous etiology. The assessment of these children by a multidisciplinary team is crucial for an accurate diagnosis and should be initiated promptly due to the potentially life-threatening nature of congenital adrenal hyperplasia, a common cause of DSD. We present a neonate born at 39 weeks with a weak cry, slight hypotonia, poor suction reflex, peculiar facies, and ambiguous genitalia. From the study carried out, the abdominopelvic ultrasound revealed a nodular structure compatible with the left gonad. Aneuploidy screening confirmed the presence of the Y chromosome. Additionally, normal endocrinological studies and the karyotype showed a genotype compatible with cri-du-chat syndrome with partial trisomy of chromosome 3. Children with cri-du-chat syndrome characteristically exhibit a cat-like cry and distinctive facial features, along with developmental delay and intellectual disability. Duplication of 3p is a rare genetic disorder, usually associated with other chromosomal anomalies and congenital malformations, namely, of the genitals.

Partial tetrasomy 18 mosaicism: Pre and postnatal diagnosis of a unique pattern.

OBJECTIVE: To present prenatal diagnosis and cytogenetic characterization of a unique pattern of partial tetrasomy 18 mosaicism. CASE REPORT: A 34-year-old woman underwent amniocentesis at 25 weeks of gestation due to anomalies detected in obstetric ultrasound. It revealed a de novo supernumerary partial isochromosome 18 in 11 of 37 metaphases of cultured amniocytes. The karyotype was 47,XX,+idic(18) (q12.3)[11]/46,XX[26]. Elective cesarean section was performed at 33 weeks of gestational age due to anhydramnios. A female symmetric small for gestational age baby with dysmorphic features and an Apgar score of 9/10/10 was born. She had a good clinical outcome during hospitalization. Postnatal peripheral blood karyotype was normal. Interphase fluorescence in situ hybridization in a sample of the oral mucosa confirmed the prenatal diagnosis. At three months of corrected age she had a normal psychomotor development. CONCLUSION: To the best of our knowledge, this is the first reported case of mosaic partial tetrasomy 18 including segments of the long arm. This newborn's relatively mild phenotype highlights the challenges of prenatal genetic counselling in mosaic cases with fetal anomalies.

Genomic imbalances defining novel intellectual disability associated loci.

BACKGROUND: High resolution genome-wide copy number analysis, routinely used in clinical diagnosis for several years, retrieves new and extremely rare copy number variations (CNVs) that provide novel candidate genes contributing to disease etiology. The aim of this work was to identify novel genetic causes of neurodevelopmental disease, inferred from CNVs detected by array comparative hybridization (aCGH), in a cohort of 325 Portuguese patients with intellectual disability (ID). RESULTS: We have detected CNVs in 30.1% of the patients, of which 5.2% corresponded to novel likely pathogenic CNVs. For these 11 rare CNVs (which encompass novel ID candidate genes), we identified those most likely to be relevant, and established genotype-phenotype correlations based on detailed clinical assessment. In the case of duplications, we performed expression analysis to assess the impact of the rearrangement. Interestingly, these novel candidate genes belong to known ID-related pathways. Within the 8% of patients with CNVs in known pathogenic loci, the majority had a clinical presentation fitting the phenotype(s) described in the literature, with a few interesting exceptions that are discussed. CONCLUSIONS: Identification of such rare CNVs (some of which reported for the first time in ID patients/families) contributes to our understanding of the etiology of ID and for the ever-improving diagnosis of this group of patients.

A Novel Noonan Syndrome RAF1 Mutation: Lethal Course in a Preterm Infant.

Noonan syndrome is a relatively common and heterogeneous genetic disorder, associated with congenital heart defect in about 50% of the cases. If the defect is not severe, life expectancy is normal. We report a case of Noonan syndrome in a preterm infant with hypertrophic cardiomyopathy and lethal outcome associated to acute respiratory distress syndrome caused by Adenovirus pneumonia. A novel mutation in the RAF1 gene was identified: c.782C>G (p.Pro261Arg) in heterozygosity, not described previously in the literature. Consequently, the common clinical course in this mutation and its respective contribution to the early fatal outcome is unknown. No conclusion can be established regarding genotype/phenotype correlation.

D-bifunctional protein deficiency: a cause of neonatal onset seizures and hypotonia.

BACKGROUND: Peroxisomal disorders are classified in two major groups: (1) peroxisome biogenesis disorders and (2) single peroxisomal enzyme/transporter deficiencies. D-bifunctional protein deficiency (OMIM #261515) is included in this last group of rare diseases and leads to an impaired peroxisomal beta-oxidation. D-bifunctional protein deficiencies are divided into four types based on the degree of activity of the 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase protein units. PATIENT DESCRIPTION: We present the first Portuguese reported type II D-bifunctional protein deficiency patient, whose neonatal clinical picture is indistinguishable from a Zellweger spectrum disease. The clinical features and the neuroimaging findings of polymicrogyria raised suspicion of the diagnosis. After biochemical analysis, D-bifunctional protein deficiency was confirmed with the identification of a homozygous p.Asn457Tyr (N457Y) mutation of the HSD17B4 gene. The patient's parents were carriers of the mutated allele, confirming the patient homozygosity status and allowing prenatal diagnosis in future pregnancies. CONCLUSIONS: D-bifunctional protein deficiency is a rare, severe disease and the final diagnosis can only be accomplished after HSD17B4 gene sequencing. Treatment is supportive, aimed at improving nutrition and growth, controlling the central nervous system symptoms, and limiting the eventual progression of liver disease.

Beckwith-Wiedemann syndrome, delayed abdominal wall closure, and neonatal intussusception--case report and literature review.

We present the extremely rare case of a male newborn with Beckwith-Wiedemann Syndrome (BWS) presenting as delayed abdominal wall closure and neonatal intussusception. Fetal ultrasound had shown omphalocele that resolved spontaneously. When feeding was attempted, he had various episodes of vomiting. An x-ray showed signs of high bowel obstruction. Jejunal intussusception was found on laparotomy. Enterectomy and primary jejuno-jejunal anastomosis was performed. During post-operative period subtle physical findings became prominent: plain hemangioma, posterior helical indentations, and macroglossia. Cardiac ultrasonography showed a patent foramen oval with small left-to-right shunt. Ultrasonography showed renal hyperplasia. Genetic study showed hypomethylation of DMR2 region of 11p15 chromosome.