In this report, we describe a rare case of prenatal diagnosis of Williams-Beuren syndrome (WBS). While the prenatal diagnosis of WBS is very rare, in the current case, WBS was diagnosed in early pregnancy. The key element was the detection of fetal hands hypotonia and generalized fetal hypotonia at 17 weeks of gestation. This led to the diagnosis of WBS by molecular karyotyping, specifically array comparative genomic hybridization (arrayCGH) of the fetal DNA. The genetic material was acquired by extraction from the fetal cells which are abundant in the amniotic fluid drawn by amniocentesis. Clinical hypotonia of the affected individuals is a clinical characteristic that is widely associated with WBS; however, fetal hypotonia has not been described as a diagnostic criterion for the prenatal diagnosis of WBS.

Schaaf-Yang syndrome (SYS) is a rare neurodevelopmental disorder caused by pathogenic variants in the MAGEL2 gene. It is usually a postnatal diagnosis in infants with muscular hypotonia and feeding difficulties. There are no cases diagnosed antenatally. During pregnancy, the most common findings reported are polyhydramnios and decreased fetal movements, which are relatively common and unspecific.We present one case of fetal clubfoot and clinodactyly in a fetus postnatally diagnosed with SYS, as well as a brief review of the prenatal findings associated with this syndrome.

Prader-Willi syndrome (PWS) is a complex genetic disorder, characterized by neonatal hypotonia, developmental delay, short stature, childhood obesity, hypogonadism, and characteristic facial features. Here we report a 21-year-old male who presented with uncontrolled glycemic status. He was diagnosed to have diabetes mellitus at the age of 15 with osmotic symptoms - polyuria, polydipsia, and polyphagia. In the early period, after diagnosis, his blood sugars were reasonably controlled with oral hypoglycemic agents. However, a year back, he was switched onto insulin therapy due to secondary OHA failure. On examination, his body mass index was 36 kg/m(2). He had bilateral gynecomastia, decreased biparietal diameter, almond shaped eyes with esotropia. He had hypogonadism and also had mild cognitive impairment. He did not have any proximal myopathy or other focal neurological deficits. Hormonal evaluation showed low testosterone and inappropriately normal fluorescence in situ hybridization suggestive of central hypogonadism. With fetal and neonatal hypotonia, delayed developmental milestones, hypogonadism, and early onset diabetes, he fulfilled the clinical criteria for the diagnosis of PWS. Multidisciplinary approach of clinicians together with family and social support are essential to bring out the optimal outcome for such syndromic cases.