Abstract：
BACKGROUND: Schaaf-Yang syndrome (SYS) is a rare neurodevelopmental disorder caused by truncating mutations of the MAGEL2 gene, located in the Prader-Willi syndrome (PWS) region. PWS and SYS have phenotypic overlap. Patients with SYS are often treated with growth hormone (GH), but evidence for the effectiveness of the treatment in patients with SYS is limited.
METHODS: This study describes 7 children with SYS. We studied their phenotype, genotype, and the effect of GH treatment on height and body mass index (BMI) during 4 years and on body composition during 1 year.
RESULTS: All patients had a normal birth weight. Most patients had hypotonia and feeding difficulties after birth (86%). Full-scale IQ ranged from <50 to 92. All patients above the age of 2 years had psycho-behavioral problems. There were no apparent correlations between the phenotype and the location of the defect in the MAGEL2 gene. Mean (95% CI) height SDS increased significantly from -1.74 (-3.55; 0.07) at start to -0.05 (-1.87; 1.77) after 4 years of GH treatment. Mean (95% CI) BMI SDS decreased significantly from 2.01 (1.02; 3.00) to 1.22 (0.18; 2.26) after 6 months and remained the same during the rest of the follow-up. Fat mass percentage SDS decreased and lean body mass did not change during 1 year of treatment in 3 patients.
CONCLUSIONS: Patients presented with a phenotype of hypotonia, respiratory insufficiency, and feeding difficulties after birth, endocrine disorders, intellectual disability, and behavioral problems. Treatment with GH significantly improved height SDS and BMI over the course of 4 years.
METHODS: This study describes 7 children with SYS. We studied their phenotype, genotype, and the effect of GH treatment on height and body mass index (BMI) during 4 years and on body composition during 1 year.
RESULTS: All patients had a normal birth weight. Most patients had hypotonia and feeding difficulties after birth (86%). Full-scale IQ ranged from <50 to 92. All patients above the age of 2 years had psycho-behavioral problems. There were no apparent correlations between the phenotype and the location of the defect in the MAGEL2 gene. Mean (95% CI) height SDS increased significantly from -1.74 (-3.55; 0.07) at start to -0.05 (-1.87; 1.77) after 4 years of GH treatment. Mean (95% CI) BMI SDS decreased significantly from 2.01 (1.02; 3.00) to 1.22 (0.18; 2.26) after 6 months and remained the same during the rest of the follow-up. Fat mass percentage SDS decreased and lean body mass did not change during 1 year of treatment in 3 patients.
CONCLUSIONS: Patients presented with a phenotype of hypotonia, respiratory insufficiency, and feeding difficulties after birth, endocrine disorders, intellectual disability, and behavioral problems. Treatment with GH significantly improved height SDS and BMI over the course of 4 years.
摘要：
背景：Schaaf-Yang综合征（SYS）是一种罕见的由MAGEL2基因截断突变引起的神经发育障碍，位于Prader-Willi综合征（PWS）区域。PWS和SYS具有表型重叠。SYS患者通常用生长激素（GH）治疗，但对SYS患者治疗有效性的证据有限.
方法：本研究描述了7名SYS患儿。我们研究了它们的表型,基因型，以及GH治疗对4年内身高和体重指数（BMI）以及1年内身体成分的影响。
结果：所有患者的出生体重均正常。大多数患者在出生后出现张力减退和进食困难（86％）。全面智商从50到92不等。所有2岁以上的患者都有心理行为问题。表型与MAGEL2基因缺陷的位置之间没有明显的相关性。平均（95％CI）身高SDS从开始时的-1.74（-3.55;0.07）显着增加到GH治疗4年后的-0.05（-1.87;1.77）。6个月后，平均（95％CI）BMISDS从2.01（1.02;3.00）显着降低至1.22（0.18;2.26），在其余的随访期间保持不变。在3例患者的治疗1年期间，脂肪质量百分比SDS降低，瘦体重没有变化。
结论：患者表现为低张力的表型，呼吸功能不全,出生后喂养困难，内分泌失调,智力残疾,和行为问题。用GH治疗在4年的过程中显着改善了身高SDS和BMI。
方法：本研究描述了7名SYS患儿。我们研究了它们的表型,基因型，以及GH治疗对4年内身高和体重指数（BMI）以及1年内身体成分的影响。
结果：所有患者的出生体重均正常。大多数患者在出生后出现张力减退和进食困难（86％）。全面智商从50到92不等。所有2岁以上的患者都有心理行为问题。表型与MAGEL2基因缺陷的位置之间没有明显的相关性。平均（95％CI）身高SDS从开始时的-1.74（-3.55;0.07）显着增加到GH治疗4年后的-0.05（-1.87;1.77）。6个月后，平均（95％CI）BMISDS从2.01（1.02;3.00）显着降低至1.22（0.18;2.26），在其余的随访期间保持不变。在3例患者的治疗1年期间，脂肪质量百分比SDS降低，瘦体重没有变化。
结论：患者表现为低张力的表型，呼吸功能不全,出生后喂养困难，内分泌失调,智力残疾,和行为问题。用GH治疗在4年的过程中显着改善了身高SDS和BMI。
