Gema Castañeda-Cisneros

SCA2 is the most prevalent of the polyQ ataxias in Cuba, India, Mexico, and Southern Italy, and the second most prevalent worldwide, accounting for 15% of all cases (^{Antenora et al., 2017}). An infantile onset is an uncommon occurrence presentation with only nine reports in the literature and is associated with extremely large CAG expansions (range 100–200 repeats). On the other hand, there are severe infantile cases with expansions between 50-70 repeats, sometimes is related with interruption CTG or CAA as occurs in adults with SCA2 and amyotrophic lateral sclerosis, which also leads to instability of ATXN2 mRNA (^{Choudhry et al., 2001}; ^{Antenora et al., 2017}), and meiotic instability a general feature of SCA2 without a familial history (^{Babovic et al., 1998}; ^{Mao et al., 2002}; ^{Moretti et al., 2004}; ^{Dirik et al., 2007}; ^{Abdel and Zaki, 2008}; ^{Paciorkowski et al., 2011}; ^{Di Fabio et al., 2012}; ^{Vinther-Jensen et al., 2013}; ^{Singh et al., 2014}). However, cases with infantile SCA2 are explain by these features; there are childhood onset cases reported with mosaicism in germ cells such as spermatozoa with larger expanded alleles more than in peripheral blood cells (^{Moretti et al., 2004}; ^{Dirik et al., 2007}; ^{Abdel and Zaki, 2008}; ^{Vinther-Jensen et al., 2013}).

The non-syndromic anterior cervical hypertrichosis (OMIM N° 600457) is a genetic disorder characterized by a patch of hair at the level of the laryngeal prominence. We present a 12-year-old boy with anterior cervical hypertrichosis and mild generalized hypertrichosis. He has no neurological, ophthalmological or skeletal anomalies. The clinical follow up is 10 years.

The appearance of untreated severe hydrocephalus with long-term survival is infrequent; here we report a case with these characteristics, mild neurological alterations and kidney and skeletal anomalies. A female patient showed severe hydrocephalus (initially mistaken with hydranencephaly) at 4 years old and left kidney ectopia (initially mistaken with renal agenesis); however, she was derived to the neurology service until she was 12 years old, when she began to present migraine and seizures. At 13 years old the patient was diagnosed with arrested hydrocephalus secondary to aqueduct stenosis, and the seizures worsen thereafter from atonic seizures to complex partial seizures (at 14 years old), presenting generalized seizures at 15 years old. At 17 years old, the seizures were more frequent despite the anticonvulsant treatment and also presented automations, she was also diagnosed with genu recurvatinn and scoliosis. The seizures finally diminished and partially controlled at 19 years old. Despite a cerebral mantle < 2.0 cm at the computer tomography, the patient always presented a satisfactory intellectual development. In this case, the relatively good and long evolution of the severe hydrocephalus is probably related with the late-onset of the disease that permitted a better development of the brain; however, the worsening of the seizures after the hydrocephalus arrested, suggests that arrest is not necessarily associated with a compensation and better evolution of the disease, at least at the beginning of the process. The presence of kidney ectopia and skeletal alterations did not associate with a known genetic disease, however a possible inheritance mechanism is not discarded.

We report an unusual case of hemimegalencephaly (HMG) associated with ipsilateral congenital-infiltrating lipomatosis of the face in a five–month-old boy. Hemimegalencephaly is a rare but unique malformation characterized by enlargement of all or parts of a cerebral hemisphere. The affected hemisphere may have focal or diffuse neuronal migration defects, with areas of polymicrogyria, pachygyria and heterotopia. Our aim was to investigate morphologic abnormalities occurring on the affected hemisphere by Magnetic Resonance Imaging (MRI), but some MRI findings were also noted outside of the affected hemicerebrum. There are a few case reports that have described various other abnormalities accompanying this condition, such as enlargement of ipsilateral brainstem, cerebellum and left lateral ventricle. MRI may be the most useful method demonstrating features of hemimegalencephaly with infiltrating lipomatosis of the face. However, studies using electroencephalogram (EEG) and brain single photon emission computerized tomography (SPECT) can show distinct variants of discharges and brain-perfusion anomalies.

Three female patients with Cantu syndrome were studied, two of whom were adults presenting with the complication of lymphoedema, as described earlier in a male patient with this syndrome. The aim of this study is to report the clinical characteristics of these three new cases and to emphasize that lymphoedema, as observed in two of the patients described here, has been observed in 11.5% of patients with Cantu syndrome and that heterochromia iridis, observed in one patient, is probably a new feature of this condition.

Snyder–Robinson syndrome (SRS, OMIM 309583) is a rare X‐linked syndrome characterized by mental retardation, marfanoid habitus, skeletal defects, osteoporosis, and facial asymmetry. Linkage analysis localized the related gene to Xp21.3–p22.12, and a G‐to‐A transition at point +5 of intron 4 of the spermine synthase gene, which caused truncation of the SMS protein and loss of enzyme activity, was identified in the original family. Here we describe another family with Snyder–Robinson syndrome in two Mexican brothers and a novel mutation (c.496T>G) in the exon 5 of the SMS gene confirming its involvement in this rare X‐linked mental retardation syndrome.

Mesomelic dysplasias (MD) are a group of skeletal disorders with exclusive or predominant shortness of the middle segment of the limbs, with or without involvement of the hands/feet or other body parts. Short stature is a usual consequence due to involvement of the lower limbs. In 2003, Camera and Camera reported an unusual upper limb MD with normal stature and radiological evidence of long bone metaphyseal dysplasia. Here, we describe a Mexican patient showing a similar clinical and radiological phenotype, in addition to esophageal atresia, palpebral ptosis and slight lower limb asymmetry. This represents the second case reported in the literature, corroborating the existence of this rare entity.