Pediatric Genetics

·         Poor vision with head enlargement in infant: suspect CANAVAN Dz

Canavan disease produces severe white matter disease as noted on the MRI. N-Acetylaspartic acid (NAA) is present in large amounts in the blood and urine and in the CNS. This lethal disease has no specific therapy.

·         hyperinsulinemic hypoglycemia, which was previously called nesidioblastosis has defects in the regulatory KATP channel, which stimulates insulin release from the pancreatic islet cells, is the most common of these disorders and may be familial or sporadic. Treatment with diazoxide or octreotide may be successful; some patients require pancreatic resection.

·         The Achilles tendon is a first site for the development of xanthomas, an area that most of us do not usually examine other than to test deep tendon reflexes.

·         Maternal UPD 15 is associated with Prader-Willi syndrome, whereas paternal UPD 15 is associated with Angelman's syndrome.

·         Paternal UPD 11 is associated with Beckwith-Wiedemann syndrome.

·         Maternal UPD 7 has been seen in some cases of Russell-Silver syndrome.

·         Paternal UPD 6 causes growth retardation (sometimes severe) and transient neonatal diabetes.

·         Maternal UPD 16 is associated with growth retardation and variable congenital anomalies but a generally good prognosis.

·         The main advantage of CVS is that it can be done between 10 and 12 weeks of gestation compared with the usual 16-week timing for amniocentesis. This permits the termination of pregnancy at a significantly earlier date in the event of major chromosomal or genetic anomalies. CVS does not permit analysis of the amniotic fluid AFP levels, so screening for neural tube defects must be performed with maternal serum AFP and ultrasound.

·         Neurofibromatosis has the highest known mutation rate per gamete per generation. The estimated mutation rate for this disorder is 1 × 10-4 per haploid genome.

·         Advanced paternal age is associated with new dominant mutations. New, common autosomal dominant mutations that have been recently mapped and identified are achondroplasia, craniosynostosis, neurofibromatosis, and Marfan syndrome.

·         Spinal muscular atrophy is the most common genetic disease that is lethal within the first year of life, an autosomal recessively inherited disease of the anterior motor neuron associated with decreased reflexes and progressive neuromuscular degeneration.

·         Hyperphagia, hypotonia, hypogonadism, and obesity: PWS