A 4-yr-old girl has exhibited severe snoring, restless sleep and increasing daytime sleepiness over the last 3 months. The physical examination showed that she was not obese but had kissing tonsils. Polysomnography demonstrated increased apnea-hypopnea index (AHI) of 5.2, and multiple sleep latency tests (MSLT) showed shortened mean sleep latency and one sleep-onset REM period (SOREMP). She was diagnosed with obstructive sleep apnea (OSA) and underwent tonsillectomy and adenoidectomy. After the surgery, her sleep became much calmer, but she was still sleepy. Another sleep test showed normal AHI of 0.2, the mean sleep latency of 8 min, and two SOREMPs. Diagnosis of OSA to be effectively treated by surgery and narcolepsy without cataplexy was confirmed. Since young children exhibiting both OSA and narcolepsy can fail to be diagnosed with the latter, it's desirable to conduct MSLT when they have severe daytime sleepiness or fail to get better even with good treatment.
Adenoidectomy ; Asian Continental Ancestry Group ; Child, Preschool ; Disorders of Excessive Somnolence/diagnosis ; Female ; Humans ; Methylphenidate/therapeutic use ; Narcolepsy/complications/*diagnosis/surgery ; Polysomnography ; Republic of Korea ; Sleep Apnea, Obstructive/*diagnosis/drug therapy/surgery ; Tonsillectomy

Lysinuric protein intolerance (LPI) is a rare inherited metabolic disease, caused by defective transport of dibasic amino acids. Failure to thrive, hepatosplenomegaly, hematological abnormalities, and hyperammonemic crisis are major clinical features. However, there has been no reported Korean patient with LPI as of yet. We recently encountered a 3.7-yr-old Korean girl with LPI and the diagnosis was confirmed by amino acid analyses and the SLC7A7 gene analysis. Her initial chief complaint was short stature below the 3rd percentile and increased somnolence for several months. Hepatosplenomegaly was noted, as were anemia, leukopenia, elevated levels of ferritin and lactate dehydrogenase, and hyperammonemia. Lysine, arginine, and ornithine levels were low in plasma and high in urine. The patient was a homozygote with a splicing site mutation of IVS4+1G > A in the SLC7A7. With the implementation of a low protein diet, sodium benzoate, citrulline and L-carnitine supplementation, anemia, hyperferritinemia, and hyperammonemia were improved, and normal growth velocity was observed.
Amino Acid Metabolism, Inborn Errors/complications/diet therapy/*genetics ; Antifungal Agents/therapeutic use ; Antigens, CD98 Light Chains/genetics ; Asian Continental Ancestry Group/*genetics ; Carnitine/therapeutic use ; Child, Preschool ; Citrulline/therapeutic use ; Diet, Protein-Restricted ; Disorders of Excessive Somnolence/complications/*diagnosis/drug therapy ; Female ; Growth Disorders/complications/*diagnosis ; Homozygote ; Humans ; Hypercalcemia/complications/*diagnosis ; Metabolic Diseases/complications/*diagnosis ; Mutation ; Nephrocalcinosis/complications/*diagnosis ; Republic of Korea ; Sequence Analysis, DNA ; Sodium Benzoate/therapeutic use ; Vitamin B Complex/therapeutic use