We report 4 children with late-onset (type III) multiple acyl-CoA dehydrogenase deficiency, also known as glutaric aciduria type II, which is an autosomal recessive disorder of fatty acid and amino acid metabolism. The underlying deficiency is in the electron transfer flavoprotein or electron flavoprotein dehydrogenase. Clinical presentations include fatal acute neonatal metabolic encephalopathies with/without organ system anomalies (types I and II) and late-onset acute metabolic crises, myopathy, or neurodevelopmental delays (type III). Two patients were identified in childhood following a metabolic crisis and/or neurodevelopmental delay, and 2 were identified by newborn metabolic screening. Our cases will illustrate the difficulty in making a biochemical diagnosis of late-onset (type III) multiple acyl-CoA dehydrogenase deficiency from plasma acylcarnitines and urine organic acids in both symptomatic and asymptomatic children. However, they emphasize the need for timely diagnosis to urgently implement prophylactic treatment for life-threatening metabolic crises with low protein/fat diets supplemented with riboflavin and carnitine.

A 2-year-old boy with an initial diagnosis of Hunter syndrome (mucopolysaccharidosis II) had a more severe phenotype than expected, which warranted further evaluation. The patient had severe infantile global neurodevelopmental delays, macrocephaly with a prominent forehead, coarse facial features with clear corneas, chronic congestion with snoring, wide-spaced teeth, short thick neck, hepatomegaly, an inguinal hernia repaired, early clawhand deformities, and severe generalized hypotonia. X chromosome microarray revealed a large deletion encompassing the genes IDS, FMR1, and AFF2 (FMR2) confirming the diagnoses of both Hunter and fragile X syndromes. This case is also a reminder to clinicians that for optimum patient care, further diagnostic testing is warranted if there is concern that a patient's phenotype is more severe or complex than would be expected for the initial neurogenetic diagnosis.

Alpha-mannosidosis (AMS) is an autosomal recessive lysosomal storage disorder which results from a deficiency of lysosomal alpha-mannosidosis activity and displays a wide range of clinical phenotypes. Patients have traditionally been divided into type I, a more severe form that presents in infancy, and type II, a milder form that typically presents in later childhood. We describe three Hispanic males who presented in infancy with relatively mild forms of AMS. They were aged between 6 and 24 years at their last assessment. Homozygous mutations in the MAN2B1 gene were found in all three patients, one of which is a newly reported mutation. Two of the patients were brothers who were homozygous for the same MAN2B1 mutation. Despite being homozygous for the same mutation, the older brother had more severe developmental delay, hearing loss, and growth retardation. This report illustrates the difficulty in determining a strict genotypephenotype correlation in AMS, and supports screening for oligosaccharides in children with neurodevelopmental delay with mild phenotypic signs and symptoms.Alpha-mannosidosis (AMS) is an autosomal recessive lysosomal storage disorder caused by lysosomal alpha-mannosidosis deficiency. 1 AMS is encoded by the MAN2B1 gene. 2 Characteristic clinical features of AMS include mental retardation,* coarse facial features, ataxia, hearing loss, dysostosis multiplex, and recurrent infections.Patients with AMS are often classified into one of two groups depending on the age at onset of the disorder and the severity of disease progression. The more severe form of AMS is designated type I or the infantile phenotype. 3,4 This type is characterized by hepato-splenomegaly, severe dysostosis multiplex, hypotonia, rapidly progressive cognitive deterioration, and death, often occurring between 3 and 12 years of age. [3][4][5] The milder form of AMS is termed type II or the juvenile-adult phenotype. 3,4 Type II AMS is characterized by normal early development, mental retardation during childhood, and survival well into adulthood. 4,5 Although patients have typically been placed into one of these two types of AMS, the clinical findings in patients may actually represent more of a continuum. 3 We describe three new cases of AMS in two families from Honduras. The patients showed variable clinical expression that correlates more readily with a continuum of clinical features. All three patients were found to have rare mutations in the MAN2B1 gene but no clear-cut genotype-phenotype correlation. Case reportsThe following patients were seen in Honduras (by KRH). The

Honduran infant mortality (20/1000) has fallen below the Latin American newborn screening target rate (<30/1000). The authors report 2 Honduran maple syrup urine disease cases and a newborn screening pilot study. The first infant, diagnosed by plasma/urine testing in the U.S., prompted this study. Although marked clinical/radiological improvement occurred after treatment, moderate neurodevelopmental delays persist at 5 years. This 1-month, prospective study used blood spot specimens from hospitalized term Honduran neonates shipped overnight to South Carolina for routine newborn screening with electronic result submission to Honduras for follow-up. Of 88 consecutive neonates (mean age: 4.2 days, standard deviation: 4.2 days) tested, 24 (0.6%) of 3837 completed tests were positive. Another infant with maple syrup urine disease, diagnosed after study completion by blood spot testing, later died. The study findings indicate that collaborative blood spot testing aids in the diagnosis of Honduran metabolic-genetic disease. Newborn screening is now needed to diagnose and treat these diseases before morbidity/mortality develops.

The authors report the rare association of Prader-Willi syndrome and short-chain acyl-CoA dehydrogenase gene variant. Prader-Willi syndrome, associated with paternal chromosome 15q11-q13 silencing, is characterized by neonatal/infantile hypotonia, growth failure, and neurodevelopmental delays in the first 1 to 2 years of life, typically followed by hyperphagia and obesity. Short-chain acyl-CoA dehydrogenase gene variant, with 625 G-to-A and 511 C-to-T changes, impairs C4-C6 fatty acid metabolism and variably causes neonatal/infantile hypotonia with developmental delays. The authors' patient continues to exhibit the classic severe growth failure of early infancy Prader-Willi syndrome at 40 months. Extensive laboratory investigations indicate that the short-chain acyl-CoA dehydrogenase gene variant is likely preventing or delaying the normal expression of the Prader-Willi syndrome phenotype.